Battery cells and modules

Abstract

To provide a novel accumulator battery that can be used in a low-temperature environment.SOLUTION: A battery cell has a flat battery body, a heat insulation part, and a heat radiation part. The heat insulation part is overlapped with at least a part of the battery body in a plan view. The heat radiation part is provided along at least a part of a lateral face of the battery body.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a storage battery. [Background technology]

[0002] Batteries are used in a variety of applications, including to power machines such as electric bicycles and small flying objects (e.g., drones).

[0003] Prior art related to storage batteries includes, for example, Patent Document 1 and Patent Document 2. Patent Document 1 discloses a laminated secondary battery that suppresses stress concentration at the attachment portion of the laminate film. Patent Document 2 discloses a battery module constructed by stacking a plurality of film-covered batteries placed on a frame. Patent Document 3 discloses a battery assembly device in which unit cells are stacked. In the battery assembly device of Patent Document 3, a heat-conducting member for heat dissipation is provided for each of the unit cells facing each other. Furthermore, a heat-insulating layer is provided between the heat-conducting members to prevent heat conduction between the unit cells. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-317312 [Patent Document 2] International Publication No. 2014 / 196331 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-084347 Summary of the Invention [Problem to be solved by the invention]

[0005] Storage batteries may not function properly in low-temperature environments. Therefore, storage batteries used in low-temperature environments require insulation to protect them from the effects of low-temperature outside air. At the same time, storage batteries are also required to dissipate heat generated inside them to the outside. The inventor has developed a new storage battery that can be used in low-temperature environments.

[0006] The present invention has been made in view of the above-mentioned problems, and one of its objects is to provide a new storage battery that can be used in low-temperature environments. [Means for solving the problem]

[0007] The battery cell of the present invention comprises: A flat battery body; a heat insulating portion that overlaps at least a portion of the battery body in a plan view; a heat dissipation portion provided along at least a portion of a side surface of the battery body, The heat dissipation section is provided at a position separated from the heat insulation section.

[0008] The battery module of the present invention is formed by stacking a plurality of battery cells of the present invention. [Effects of the Invention]

[0009] According to the present invention, a new storage battery that can be used in low-temperature environments is provided. [Brief explanation of the drawings]

[0010] The above-mentioned objects, as well as other objects, features and advantages, will become more apparent from the preferred embodiments described below and the accompanying drawings.

[0011] [Figure 1] 1 is a perspective view showing an example of a battery cell according to Embodiment 1. FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of a battery cell housed in a frame body. [Figure 3] 10 is a diagram illustrating a case in which heat insulating portions are provided on both the upper and lower surfaces of a battery cell. FIG. [Figure 4] 10A to 10C are diagrams illustrating variations in sealing using a sealing material. [Figure 5] 10 is a diagram illustrating an example of a heat insulating portion that is provided so as to overlap the battery body but not the peripheral portion of the sealing material. FIG. [Figure 6] 10A and 10B are diagrams illustrating an example of a bag-shaped sealing material. [Figure 7] FIG. 10 is a perspective view illustrating a battery module according to a second embodiment. [Figure 8] FIG. 10 is a YZ plan view of a battery module according to a second embodiment. [Figure 9] FIG. 10 is a diagram illustrating a case in which a heat insulating portion is provided on the upper surface of each battery cell. [Figure 10] FIG. 1 is a perspective view of a battery module made up of battery cells stacked using a frame body. [Figure 11] FIG. 1 is an AB cross-sectional view of battery cells stacked using a frame. [Figure 12] FIG. 2 is a diagram illustrating a battery module housed in a housing. [Figure 13] 10A and 10B are diagrams illustrating an example of a battery module housed in a housing with a portion of the periphery bent downward; DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all drawings, like components are designated by like reference numerals, and their description will be omitted where appropriate. Furthermore, unless otherwise specified, each block in the block diagram represents a functional configuration, not a hardware configuration.

[0013] 1 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 therein. For example, the shape of the battery body 110 is a rectangular parallelepiped. However, the shape of the battery body 110 does not have to be strictly a rectangular parallelepiped, and for example, it may be a rectangular parallelepiped with each side or vertex chamfered.

[0014] The shape of the battery body 110 is not limited to a rectangular parallelepiped, and may be flat, i.e., the length of the side of the surface of the battery body 110 when viewed in plan from the top or bottom (the surface of the battery body 110 when viewed in the XY plane in FIG. 1) is greater than the thickness of the battery body 110 (the size in the Z direction in FIG. 1). The shape of the surface of the battery body 110 when viewed in plan from the top or bottom can be any shape (for example, an ellipse). Furthermore, the sizes of the top and bottom of the battery body 110 do not have to be the same.

[0015] The battery cell 100 is a cell of a secondary battery such as a lithium ion battery, and has a structure in which a battery body 110 is sealed with a sealing material 140. The sealing material 140 is a member that seals the battery body 110. For example, the sealing material 140 is a laminate film. In this case, the battery body 110 is laminated and sealed with the sealing material 140. For example, the battery body 110 is sealed between two films that constitute the sealing material 140. This film extends outward from the battery body 110 around the entire periphery of the battery body 110. Hereinafter, this portion that extends outward from the battery body 110 will be referred to as a peripheral portion (reference numeral 142) of the sealing material 140. In other words, the peripheral portion 142 is a portion of the sealing material 140 that is located around the side surface of the battery body 110. The peripheral portion 142 is also a portion where the two films that constitute the sealing material 140 face each other without the battery body 110 in between.

[0016] The battery cell 100 further includes a heat insulating section 120, a heat dissipation section, and electrodes 160. The heat insulating section 120 is made of a material that has a lower thermal conductivity than at least the sealing material 140.

[0017] The heat insulating section 120 is preferably a member having a plurality of voids therein. The plurality of voids may be independent of one another. Alternatively, at least two voids may be connected to one another. The heat insulating section 120 having a plurality of voids therein is formed of a porous material such as nitrile synthetic rubber. However, the heat insulating section 120 may also be formed of a material other than a porous material (for example, polyurethane).

[0018] The thermal conductivity of the heat insulating section 120 is preferably 0.02 W / mK or more, and more preferably 0.05 W / mK or less.

[0019] The heat insulating section 120 is provided so as to overlap at least a part of the battery body 110 in the XY plane view. From the viewpoint of heat insulation, it is preferable that the heat insulating section 120 has approximately the same area as the battery body 110 in the XY plane view and is provided so as to overlap with approximately the entire area of ​​the battery body 110.

[0020] The thickness of the heat insulating section 120 is preferably 2 mm or more. The thickness of the heat insulating section 120 is preferably 3 mm or less. The thickness of the heat insulating section 120 may be uniform or non-uniform. For example, if the temperature distribution within the battery cell 100 becomes non-uniform when the battery cell 100 is in use, it is preferable to make the thickness of the heat insulating section 120 non-uniform to match the temperature distribution. Specifically, the thickness of the region of the heat insulating section 120 that overlaps in plan view with a region within the battery cell 100 that becomes relatively hot is made relatively thin. On the other hand, the thickness of the region of the heat insulating section 120 that overlaps with a region within the battery cell 100 that becomes relatively cold is made relatively thick.

[0021] For example, in a plan view, the thickness of the center of the heat insulating section 120 is made thinner than other portions. This is because, when the peripheral section 142 functions as a heat dissipation section as will be described later, the heat dissipation effect of the peripheral section 142 makes it easier for the temperature of the portion of the battery cell 100 closer to the peripheral section 142 (portion farther from the center of the heat insulating section 120) to be lower than that of the portion farther from the peripheral section 142 (portion closer to the center of the heat insulating section 120). Alternatively, for example, the battery cell 100 may be tested before operation to ascertain the temperature distribution within the battery cell 100 in advance, and the thickness distribution of the heat insulating section 120 may be determined based on this temperature distribution.

[0022] The planar shape of the heat insulating section 120 is not limited to the rectangular shape shown in Fig. 1, and may be any shape. Furthermore, the heat insulating section 120 may have a plurality of openings in plan view.

[0023] The heat insulating section 120 may be attached directly to the sealing material 140, or may be attached to the sealing material 140 via a separate member. In the former case, for example, the heat insulating section 120 is welded to the sealing material 140. In the latter case, for example, the heat insulating section 120 is attached to the sealing material 140 with an adhesive material such as double-sided tape.

[0024] The heat dissipation section is a component that serves to dissipate heat generated from the battery main body 110 to the outside of the battery cell 100. For example, the heat dissipation section is formed of air, metal, or the like. The heat conductivity of the heat dissipation section is preferably 0.4 W / mK or more. Furthermore, the heat conductivity of the heat dissipation section is preferably 0.6 W / mK or less. In particular, the heat conductivity of the heat dissipation section is preferably 0.5 W / mK.

[0025] The heat dissipation portion is provided along at least a part of the side surface of the battery body 110. For example, the heat dissipation portion is provided around the entire periphery of the side surface of the battery body 110.

[0026] In FIG. 1, the heat dissipation portion is formed by a sealing material 140. Specifically, the sealing material 140 has a peripheral portion 142 located around the side surface of the battery body 110, and this peripheral portion 142 functions as the heat dissipation portion. The heat dissipation portion may be a part of or the entire peripheral portion 142. It is preferable that the peripheral portion 142 functioning as the heat dissipation portion has an area of ​​20% or more of the area of ​​the entire battery cell 100 in the YX plan view.

[0027] When the sealing material 140 is made of a laminate film and the peripheral portion 142 functions as a heat dissipation portion, it is preferable that the laminate film contains a metal material (e.g., aluminum). For example, the laminate film has a structure in which a resin layer for thermocompression bonding and a metal layer for heat dissipation are laminated. The thickness of the metal layer is preferably 20% or more of the entire laminate film. Furthermore, it is preferable that the thickness of the metal layer is 50% or less of the entire laminate film.

[0028] The heat dissipation portion may be formed from something other than the peripheral portion 142 of the sealing material 140. For example, the battery cell 100 may be housed in a frame, and a part of this frame may function as the heat dissipation portion. The frame is preferably made of a material with high thermal conductivity, such as resin.

[0029] 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 electrodes 160. The frame 10 is also formed to hold the entire periphery of the peripheral portion 142. However, the frame 10 does not necessarily have to hold the entire periphery of the peripheral portion 142, and may be formed to hold only a portion of the peripheral portion 142. It is preferable that the frame 10 be lightweight. Specifically, it is preferable that the weight per unit volume is about 1 g.

[0030] In the explanation so far, the battery body sealed with a sealing material (battery cell 100 in FIG. 2) has been called a battery cell, but the battery body sealed with a sealing material and the frame that houses it (battery cell 100 and frame 10 in FIG. 2) can also be called a battery cell together. For convenience of explanation, in the following, as in the explanation so far, the battery body sealed with a sealing material will be called a battery cell, excluding the frame.

[0031] The electrode 160 is connected to the battery body 110 and is drawn out to the outside of the sealing material 140. In FIG. 1, two electrodes 160 are provided side by side on one short side of the battery cell 100 in the XY plane view. However, the electrodes 160 may be provided at any position. For example, two electrodes 160 may be provided side by side on one long side of the battery cell 100, one electrode 160 may be provided on each of two opposing short sides, or one electrode 160 may be provided on each of two opposing long sides.

[0032] <Actions and Effects> The battery cell 100 of this embodiment is provided with a heat insulating section 120 at a position that overlaps at least a portion of the battery body 110 in a plan view. This heat insulating section 120 can reduce the effect of low-temperature outside air on the battery body 110. As a result, the low-temperature characteristics of the battery cell 100 can be improved.

[0033] Furthermore, the battery cell 100 of this embodiment is provided with a heat dissipation portion along at least a portion of the side surface of the battery body 110. This heat dissipation portion allows heat generated by the battery body 110 to be released to the outside, thereby preventing the battery body 110 from becoming too hot.

[0034] Furthermore, the heat insulating section 120 and the heat dissipation section are provided at positions separated from each other in the battery cell 100. This prevents the heat insulating section 120 and the heat dissipation section from interfering with each other, thereby preventing a decrease in the efficiency of heat insulation or heat dissipation.

[0035] <Other variations of Battery Cell 100> 1 is provided on the upper surface side (-Z side) of the battery cell 100. However, the heat insulating section 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.

[0036] 3 is a diagram illustrating a case in which heat insulating sections 120 are provided on both the upper and lower surfaces of the battery cell 100. The heat insulating sections 120 provided on the upper surface and the lower surface may be the same size or different sizes. Furthermore, these heat insulating sections 120 may be arranged so that they at least partially overlap in a plan view, or so that they do not overlap in a plan view.

[0037] 1, the sealing material 140 seals the battery body 110 so that the portions that are more convex than the electrodes 160 in the YZ plane view are present on both the upper and lower surfaces of the battery body 110. However, the sealing material 140 may seal the battery body 110 so that the portions that are more convex than the electrodes 160 in the YZ plane view are present on only one of the upper and lower surfaces of the battery body 110.

[0038] 4A and 4B are diagrams illustrating variations in sealing by the sealing material 140. In Fig. 4A, the portion that is more convex than the electrode 160 in YZ plane view is present only on the upper surface side of the battery body 110. On the other hand, in Fig. 4B, the portion that is more convex than the electrode 160 in YZ plane view is present only on the lower surface side of the battery body 110.

[0039] As shown in FIG. 4, even when the portion that is more convex than the electrode 160 in the YZ plane view exists only on either the upper surface side or the lower surface side of the battery body 110, 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 sides.

[0040] Here, the heat insulating portion 120 is assumed to be provided on a side that is not more convex than the electrode 160 in a YZ plane view. FIG. 5 is a diagram illustrating a case in which the heat insulating portion 120 is provided on a side that is not more convex than the electrode 160 in a YZ plane view. In this case, the heat insulating portion 120 can also be provided at a position that overlaps with the peripheral portion 142 in a plan view. However, in terms of a balance between insulation and heat dissipation, it is preferable that the heat insulating portion 120 be provided so as to overlap with the battery body 110 but not with the peripheral portion of the sealing material 140 (see FIG. 5). From the viewpoint of insulation, it is preferable that the heat insulating portion 120 be provided so as to overlap with substantially the entire battery body 110.

[0041] The sealing material 140 is not limited to being made up of two films as described above. For example, the sealing material 140 may be made up of a bag-shaped film. FIG. 6 is a diagram illustrating an example of a bag-shaped sealing material 140. Before the battery cell 100 is inserted, the sealing material 140 has only one of its four sides open. The battery cell 100 is then inserted through this opening, and the opening is sealed (for example, by laminating) to form a sealed battery cell 100.

[0042] [Embodiment 2] 7 is a perspective view illustrating a battery module 200 according to embodiment 2. The battery module 200 is an assembled battery configured by stacking a plurality of battery cells 100.

[0043] Fig. 8 is a YZ plan view of a battery module 200 according to embodiment 2. Each battery cell 100 in Fig. 8 is provided with heat insulating sections 120 on both the upper and lower surfaces, similar to the battery cell 100 shown in Fig. 3. Furthermore, in Fig. 8, two adjacent battery cells 100 are stacked with an adhesive material 150 (hereinafter referred to as adhesive material) interposed therebetween. The adhesive material is, for example, double-sided tape.

[0044] As described in the first embodiment, the heat insulating section 120 may be provided on only one of the upper and lower surfaces of the battery cell 100. When the heat insulating section 120 is provided on only one of the upper and lower surfaces of the battery cell 100, it is preferable that all of the multiple battery cells 100 have the heat insulating section 120 on the same side. FIG. 9 is a diagram illustrating a case in which the heat insulating section 120 is provided on the upper surface of each battery cell 100. The battery cell 100 in FIG. 9 differs from the battery cell 100 shown in FIG. 3 in that the heat insulating section 120 is provided only on the upper side. By providing the heat insulating section 120 on the same surface of each battery cell 100 in this way, the heat insulating section 120 is always located between two adjacent battery cells 100. This prevents heat transfer between two adjacent battery cells 100.

[0045] Here, the method for maintaining the stacked state of the plurality of battery cells 100 is not limited to the method of fixing the battery cells 100 together using the adhesive material 150. For example, when adjacent battery cells 100 have heat insulating sections 120 on opposing surfaces, the opposing surfaces of the heat insulating sections 120 may be engaged with each other. In this case, the surfaces of the heat insulating sections 120 are processed so that the opposing surfaces of the heat insulating sections 120 engage with each other. For example, the heat insulating sections 120 are provided with an uneven shape, and the processing is performed so that the convex portion of one heat insulating section 120 fits into the concave portion of the other heat insulating section 120. Note that various other processes can be used to process the surfaces so that they engage with each other. Alternatively, for example, the stacked state of the battery cells 100 may be maintained by binding the plurality of battery cells 100 that constitute the battery module 200 with tape or the like.

[0046] The battery cells 100 may be stacked using a frame 10. Fig. 10 is a perspective view of a battery module 200 made up of battery cells 100 stacked using a frame 10. Fig. 11 is a cross-sectional view taken along line AB of Fig. 10.

[0047] When using the frame bodies 10, for example, two adjacent frame bodies 10 can be maintained in a stacked state by engaging a part of one frame body 10 with a part of the other frame body 10 (for example, a part of one frame body 10 grips a part of the other frame body 10). Alternatively, for example, an adhesive material 150 may be provided between two adjacent frame bodies 10 to maintain the stacked state. Furthermore, the frame bodies 10 may be maintained in a stacked state by binding the battery modules 200 with tape or the like.

[0048] The battery module 200 may be housed in a housing. FIG. 12 is a diagram illustrating the 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 viewpoint of heat dissipation, it is preferable that the housing 20 be provided with holes through which air can pass. It is preferable that as many holes as possible be provided uniformly on each side of the housing 20.

[0049] When the battery module 200 is housed in the housing 20, a portion of the peripheral portion 142 of the sealing material 140 may be folded. Fig. 13 is a diagram illustrating an example of the battery module 200 housed in the housing 20 with a portion of the peripheral portion 142 folded. The battery module 200 housed in the housing 20 in Fig. 13 is the battery module exemplified in Fig. 8. This allows the size of the housing 20 (the size of the battery module 200) to be reduced.

[0050] 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 other configurations can also be adopted. Below, examples of reference aspects are given. 1. A flat battery body; a heat insulating portion that overlaps at least a portion of the battery body in a plan view; a heat dissipation portion provided along at least a portion of a side surface of the battery body. 2. A sealing material that seals the battery body is provided, the sealing material has a peripheral portion located around the periphery of a side surface of the battery body, 1. The battery cell according to 1, wherein the heat dissipation portion is at least a part of the peripheral portion. 3. A battery pack having a sealing material for sealing the battery body and a frame body, the sealing material has a peripheral portion located around the periphery of a side surface of the battery body, the frame holds the peripheral portion, 3. The battery cell according to 1. or 2., wherein the heat dissipation portion is the frame body. 4. The battery cell according to any one of 1. to 3., wherein the heat dissipation portion has a thermal conductivity of 0.4 W / mK or more and 0.6 W / mK or less. 5. The battery cell according to any one of 1. to 4., wherein the thermal conductivity of the heat insulating portion is 0.02 W / mK or more and 0.05 W / mK or less. 6. The battery cell according to any one of 1. to 5., wherein the heat insulating portion has a plurality of voids. 7. The battery cell according to any one of 1. to 6., wherein the heat insulating portion is provided on both the upper and lower surfaces of the battery body. 8. The battery cell according to any one of 1. to 7., which has a sealant that seals the battery body so that there are convex portions on both the upper and lower surfaces of the battery body. 9. A battery module in which a plurality of battery cells according to any one of 1. to 8. are stacked.

[0051] This application claims priority based on Japanese Patent Application No. 2017-182241, filed September 22, 2017, the disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A flat battery body; a heat insulating portion that overlaps at least a portion of the battery body in a plan view; a heat dissipation portion provided along at least a portion of a side surface of the battery body; a sealing material that seals the battery body, the heat dissipation section is provided at a position spaced apart from the heat insulation section, the sealing material has a peripheral portion located around the periphery of a side surface of the battery body, the heat dissipation portion is at least a part of the peripheral portion, The peripheral portion has an area of ​​20% or more of the entire area of ​​the battery cell in a plan view.

2. a sealing material that seals the battery body and a frame body, the sealing material has a peripheral portion located around the periphery of a side surface of the battery body, the frame holds the peripheral portion, The battery cell according to claim 1 , wherein the heat dissipation portion is the frame body.

3. The battery cell according to claim 1 or 2, wherein the heat dissipation portion has a thermal conductivity of 0.4 W / mK or more and 0.6 W / mK or less.

4. The battery cell according to claim 1 , wherein the thermal conductivity of the heat insulating portion is 0.02 W / mK or more and 0.05 W / mK or less.

5. The battery cell according to claim 1 , wherein the heat insulating portion has a plurality of voids.

6. The battery cell according to claim 1 , wherein the heat insulating portion is provided on both an upper surface side and a lower surface side of the battery body.

7. The battery cell according to claim 1 , further comprising a sealant that seals the battery body so that convex portions are present on both the upper and lower surfaces of the battery body.

8. A battery module comprising a plurality of battery cells according to claim 1 stacked together.

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