Battery pack

Abstract

The partial structure of the battery pack includes: a battery group formed by stacking multiple layers of cylindrical batteries arranged in a plane, the cylindrical batteries belonging to adjacent layers being arranged with a half-pitch offset between layers; a heat-conducting plate in contact with the side of the cylindrical battery arranged on the opposite surface, composed of a heat-conducting corrugated plate material, and extending through the gaps between the cylindrical batteries along the arrangement direction of the cylindrical batteries within the layer in a plane orthogonal to the central axis of the cylindrical battery, or a first cross direction intersecting the arrangement direction, or a second cross direction intersecting the arrangement direction and the first cross direction; and a heat sink arranged on the side of the battery group, connected to the end edge of the heat-conducting plate, with the cylindrical batteries each in contact with at least two heat-conducting plates.

Description

[0001] Cross-referencing of related applications

[0002] This application claims priority based on Japanese Patent Application No. 2020-41169, filed on March 10, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the construction of a battery pack consisting of multiple batteries. Background Technology

[0004] In applications such as electric vehicles where high voltage and large capacity are required for power supplies, battery packs containing multiple batteries are used. Battery packs require miniaturization for ease of installation; however, if miniaturization increases battery density, heat dissipation from the batteries becomes an issue. Furthermore, regarding battery packs used in low-temperature environments, external heating is sometimes required, raising concerns about warm-up time.

[0005] U.S. Patent Application Publication No. 2011 / 0212356 discloses a technique for cooling cylindrical batteries by allowing fluid to flow through them in a wavy, extended flow path. Japanese Patent Application Publication No. 2018-60594 discloses a technique for improving thermal conductivity through carefully designed cylindrical battery configurations. Japanese Patent Application Publication No. 2016-178066 discloses a technique for cooling cylindrical batteries by supplying air between them. Summary of the Invention

[0006] The requirement is for a battery pack with a small and simple structure that provides good heat dissipation and excellent thermal response.

[0007] According to a first aspect of the present invention, a partial structure of a battery pack is provided. The partial structure of the battery pack includes: a battery group, which is a battery group formed by multiple layers of cylindrical batteries arranged in a plane and stacked, wherein the cylindrical batteries belonging to adjacent layers are arranged with their spacing staggered by half a pitch between layers; a heat-conducting plate, which contacts the side surfaces of the cylindrical batteries arranged on both sides, is made of a thermally conductive corrugated plate, and extends through the gaps between the cylindrical batteries along the arrangement direction of the cylindrical batteries in the layer in a plane orthogonal to the central axis of the cylindrical batteries, or a first intersecting direction intersecting the arrangement direction, or a second intersecting direction intersecting both the arrangement direction and the first intersecting direction; and a heat sink, which is disposed on the side of the battery group and connected to the end edge of the heat-conducting plate, wherein each cylindrical battery contacts at least two heat-conducting plates.

[0008] According to the above method, the arrangement density of the cylindrical batteries can be increased by staggering them, enabling miniaturization of the battery pack. Furthermore, heat dissipation can be improved by using a heat-conducting plate made of conductive corrugated material, with a simple structure corresponding to the staggered arrangement of the cylindrical batteries. In addition, compared to burying the cylindrical batteries between them with thermally conductive material, using a heat-conducting plate reduces the heat capacity of the battery pack and improves thermal response.

[0009] In the above configuration, the battery pack may have a first side and a second side in the direction of layer overlap, the number of cylindrical batteries belonging to each layer increases one by one from the first side toward the second side, the heat sink is disposed at least on the second side, and the heat-conducting plate includes: a first-direction heat-conducting plate extending along the first intersecting direction; and a second-direction heat-conducting plate extending along the second intersecting direction. Heat-conducting plates that traverse the layers are added accordingly to the increase in the number of cylindrical batteries, and each heat-conducting plate is connected to the heat sink on the second side.

[0010] According to the above method, even in an arrangement where the number of cylindrical batteries increases from the first side to the second side, a heat-conducting plate can be configured.

[0011] In the above manner, the end edge of the additional heat-conducting plate facing the first side may not be connected to other heat-conducting plates.

[0012] According to the above method, the end edge of the additional heat-conducting plate facing the first side can be connected to other heat-conducting plates.

[0013] In the above configuration, the heat sink can be configured such that, in addition to the second side, the heat sink is also disposed on the first side, and the heat-conducting plate that traverses the layer closest to the first side is connected to the heat sink disposed on the first side.

[0014] According to a second aspect of the present invention, a battery pack is provided in which cylindrical batteries are arranged in a hexagonal configuration, wherein a plurality of cylindrical batteries arranged in a hexagonal pattern are arranged concentrically. The battery pack has partial structures of any of the battery packs of the first aspect in portions corresponding to the sides of the hexagon.

[0015] According to another aspect of the invention, a battery pack is provided having a structure in which battery pack modules belonging to the layers of cylindrical batteries are combined one by one from a first side toward a second side to form a hexagon. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing a cross-section of the battery pack of this embodiment orthogonal to the cylindrical battery.

[0017] Figure 2 It is an exploded perspective view that schematically shows a portion of the battery pack's structure.

[0018] Figure 3 This is a cross-sectional view schematically illustrating an example of a portion of the battery pack's construction.

[0019] Figure 4 This is a cross-sectional view schematically illustrating a portion of the structure of a battery pack.

[0020] Figure 5 It is a cross-sectional view schematically showing a portion of the structure of another battery pack. Detailed Implementation

[0021] The embodiments of the present invention will now be described with reference to the accompanying drawings. Figure 1 This is a diagram showing the battery pack 10 of this embodiment, and is a schematic diagram showing a cross-section orthogonal to the central axis of the so-called cylindrical battery 12, which has a cylindrical shape. Figure 2 It is a diagram showing a portion of the battery pack 10, and is an exploded perspective view of the components.

[0022] Multiple cylindrical batteries 12 are arranged in an annular space between two concentrically arranged cylindrical inner heat sinks 14 and outer heat sinks 16. All cylindrical batteries 12 are identical in shape and arranged with their central axes parallel. The inner cylindrical batteries 12 are hexagonal, and the outer cylindrical batteries 12 are arranged in a hexagonal configuration to surround these inner and outer cylindrical batteries 12. Adjacent hexagonal cylindrical batteries are arranged with a half-pitch staggered spacing. Similarly, the outer cylindrical batteries 12 are arranged, forming four hexagons in total with respect to the battery pack 10. Further outwards, cylindrical batteries 12 are arranged without the vertices of their hexagonal shapes. This staggered arrangement of the cylindrical batteries 12 with a half-pitch staggered spacing allows other cylindrical batteries 12 to enter the recesses formed by the outer shapes of two cylindrical batteries 12, thus increasing the density of the cylindrical batteries 12.

[0023] A corrugated heat-conducting plate 18 is arranged from the inside out, extending to fill the gaps in the cylindrical battery 12. The heat-conducting plate 18 is corrugated and made of a thermally conductive material, utilizing the material itself for heat conduction. The heat-conducting plate 18 can be formed, for example, from a metal plate, particularly an aluminum plate. The cylindrical battery 12 and the heat-conducting plate 18 are approximately equal in size along the central axis of the cylindrical battery 12. The heat-conducting plate 18 has a portion that is curved along the side of the cylindrical battery 12. The heat-conducting plate 18 contacts the side of the cylindrical battery 12 locally and in a strip-shaped region extending along the length of the cylindrical battery 12. The heat-conducting plate 18 can be in direct contact with the cylindrical battery 12, or it can be in contact via an adhesive or the like. This contact improves thermal conductivity compared to contact with air.

[0024] The inner edges of several heat-conducting plates 18 are connected to the inner heat sink 14, and the outer edges are connected to the outer heat sink 16. The remaining heat-conducting plates 18 are only connected to the outer heat sink 16. The heat generated in the cylindrical battery 12 is conducted through the heat-conducting plates 18 and flows to the inner heat sink 14 and the outer heat sink 16 connected to the heat-conducting plates 18.

[0025] The inner heat sink 14 and the outer heat sink 16 are made of thermally conductive materials, such as metal, particularly aluminum, and dissipate heat from the heat-conducting plate 18 from the side opposite to the surface opposite to the cylindrical battery 12. Additionally, fins can be provided on the surface of one or both of the inner heat sink 14 and the outer heat sink 16 to promote heat dissipation. Furthermore, a flow path can be formed inside one or both of the inner heat sink 14 and the outer heat sink 16, allowing fluid to flow through and dissipate heat to the fluid.

[0026] End panels 20 and 22 are provided at both ends of the space between the inner heat sink 14 and the outer heat sink 16, and the space where the cylindrical battery 12 is disposed is set as a closed space.

[0027] Figure 3 It is an enlarged representation of a portion corresponding to one side of the hexagonal shape in which the cylindrical battery 12 is arranged, for example, by... Figure 1 A diagram of the structure of the part enclosed by the dotted line.

[0028] The four cylindrical batteries 12, located near the inner heat sink 14, are arranged in a single plane, parallel to each other along their central axes. Figure 3The four cylindrical batteries 12 are arranged in a left-right direction. A layer is formed by these four cylindrical batteries 12. This layer is designated as the first arrangement layer 24A, and the cylindrical batteries belonging to this first arrangement layer 24A are designated as cylindrical batteries 12A. A second arrangement layer 24B is formed by five cylindrical batteries 12 adjacent to the first arrangement layer 24A. The cylindrical batteries belonging to this second arrangement layer 24B are designated as cylindrical batteries 12B. The cylindrical batteries 12B are arranged in a plane, parallel to their central axes. Figure 3 The cylindrical batteries 12A and 12B are arranged in a left-right direction. The arrangement of the cylindrical batteries 12A and 12B is staggered by half a pitch, and they are inserted into the recessed portions formed on the sides of adjacent cylindrical batteries in the adjacent arrangement layer. A third arrangement layer 24C is formed by six cylindrical batteries 12 adjacent to the second arrangement layer 24B, and a fourth arrangement layer 24D is formed by seven cylindrical batteries 12 adjacent to the third arrangement layer 24C. The cylindrical batteries belonging to the third arrangement layer 24C are designated as cylindrical battery 12C, and the cylindrical batteries belonging to the fourth arrangement layer 24D are designated as cylindrical battery 12D. The cylindrical batteries 12C and 12D belonging to the third and fourth arrangement layers 24C and 24D are also configured to be staggered by half a pitch from the cylindrical batteries in the first and second arrangement layers 24A and 24B, respectively. In the absence of needing to distinguish between the first to fourth arrangement layers 24A to 24D, and in the case of generalization, they are referred to as arrangement layer 24.

[0029] A partial structure of the battery pack 10, including the battery assembly 26 composed of the first to fourth layers 24A to 24D, will be described. This partial structure is described in the direction of overlap of each layer 24. Figure 3 The upper part (in the vertical direction) includes: an inner heat sink 14, which is disposed on the first side of the battery pack 26. Figure 3 The middle side is the lower side); and the outer heat sink 16 is disposed on the second side opposite to the first side. Figure 3 (The middle is the top side). The first side and the second side are the inner side and the outer side in the cylindrical battery pack 10, respectively. In the following description, the first side will be referred to as the inner side and the second side as the outer side.

[0030] Regarding each of the arrangement layers 24 constituting the battery pack 26, the cylindrical batteries 12 belonging to each arrangement layer 24 increase one by one from the inner first arrangement layer 24A to the outer fourth arrangement layer 24D. The cylindrical batteries 12 are neatly arranged in the plane defined by each arrangement layer 24; furthermore, they are neatly arranged in one plane even along two directions intersecting the arrangement layer 24. The direction in which the cylindrical batteries 12 are arranged within each arrangement layer 24 is denoted as the battery arrangement direction U. Even in two directions intersecting at 60° relative to the battery arrangement direction U, the cylindrical batteries 12 are neatly arranged; these directions are denoted as the first intersecting direction V and the second intersecting direction W. The gaps between the cylindrical batteries 12 extend along the aforementioned directions U, V, and W.

[0031] There are six heat-conducting plates 18 associated with the battery pack 26, designated by numerals 18A, 18B, 18C, 18D, 18E, and 18F. Additionally, a heat-conducting plate 18G is provided associated with the cylindrical battery 12, located further outward than the fourth layer 24D and indicated by a dashed line. Each cylindrical battery 12 is in contact with at least two heat-conducting plates 18. The cylindrical battery 12 is in contact with both the front and back sides of each heat-conducting plate 18. Furthermore, the heat-conducting plates 18 do not contact each other, nor do they intersect. The cylindrical batteries 12 located at the ends of each layer 24... Figure 3 The diagram shows contact with only one heat-conducting plate 18, however, as Figure 1 It is shown to be in contact with the heat-conducting plate 18 belonging to the adjacent local structure, and is actually in contact with two heat-conducting plates 18.

[0032] Heat-conducting plates 18A-18C traverse the first to fourth arrangement layers 24A-24D, with their inner edges connected to the inner heat sink 14 and their outer edges connected to the outer heat sink 16. Heat-conducting plates 18A and 18C are first-direction heat-conducting plates extending along the first intersecting direction V, and heat-conducting plate 18B is a second-direction heat-conducting plate extending along the second intersecting direction W. Heat-conducting plates 18A-18C respectively enter the gaps in the first arrangement layer 24A at three locations formed between adjacent cylindrical batteries 12A, traversing the first arrangement layer 24A.

[0033] There are five cylindrical batteries 12B belonging to the second arrangement layer 24B, and the gaps between adjacent cylindrical batteries 12B are four, which is one more gap than that in the first arrangement layer 24A. A heat-conducting plate 18D is added by burying this additional portion. The heat-conducting plate 18D traverses the second arrangement layer 24B, extends outward along the second intersecting direction W, and connects to the outer heat sink 16. The heat-conducting plate 18D is a second-direction heat-conducting plate extending along the second intersecting direction W. The heat-conducting plate 18D also traverses the third and fourth arrangement layers 24C and 24D in addition to the second arrangement layer 24B. Furthermore, the heat-conducting plate 18D traverses the arrangement layer 24, which here means traversing the closest part of the adjacent cylindrical batteries 12, meaning that it is configured to contact the cylindrical batteries 12 on both sides, and is not required to be configured along the entire thickness direction of the arrangement layer 24.

[0034] There are six cylindrical batteries 12C belonging to the third layer 24C, with five gaps between adjacent cylindrical batteries 12C, an increase of one gap compared to the second layer 24B. A heat-conducting plate 18E is added by burying this additional portion. The heat-conducting plate 18E traverses the third layer 24C, extends outward along the first intersecting direction V, and connects to the outer heat sink 16. The heat-conducting plate 18E is a first-direction heat-conducting plate extending along the first intersecting direction V. The heat-conducting plate 18E also traverses the fourth layer in addition to the third layer 24C.

[0035] There are seven cylindrical cells 12D belonging to the fourth layer 24D, and the gaps between adjacent cylindrical cells 12D are six, which is one more gap than that in the third layer 24C. A heat-conducting plate 18F is added by burying this additional portion. The heat-conducting plate 18F traverses the fourth layer 24D, extends outward along the second intersecting direction W, and connects to the outer heat sink 16. The heat-conducting plate 18F is a second-direction heat-conducting plate extending along the second intersecting direction W.

[0036] The additional heat-conducting plates 18D to 18F change from a structure closer to the inner edge to an alternating direction of extension, but the order is not limited to this. For example, all the additional heat-conducting plates can extend along either the first or the second intersecting direction.

[0037] The heat generated in the cylindrical battery 12 is conducted through the heat-conducting plate 18 and flows to the inner heat sink 14 and the outer heat sink 16. Furthermore, when one cylindrical battery 12 overheats abnormally, the cylindrical batteries 12 located across the heat-conducting plate 18 utilize the heat-conducting plate 18 to diffuse heat and suppress temperature rise. Additionally, for the cylindrical batteries 12 that are directly opposite the abnormally overheating cylindrical batteries 12 without passing through the heat-conducting plate 18, a gap is provided between the cylindrical batteries 12; by providing an air layer, temperature rise can be suppressed.

[0038] Figure 4This is a diagram showing another way of representing the partial structure of the battery pack. Regarding this method, relative to... Figure 3 The partial structures shown differ in the construction of the heat-conducting plate, but are identical in other aspects; therefore, they are labeled with the same symbols and their descriptions are omitted.

[0039] Figure 4 The heat-conducting plates 28A to 28F of the partial structure of the battery pack shown correspond to the aforementioned heat-conducting plates 18A to 18F, respectively. Regarding heat-conducting plates 28A to 28F, unless there is a need for distinction or they are collectively referred to as heat-conducting plates 28, A to F are omitted. Furthermore, the heat-conducting plate 28G associated with the cylindrical battery 12 arranged on the outer side of the fourth arrangement layer 24D corresponds to the aforementioned heat-conducting plate 18G.

[0040] Heat-conducting plates 28A to 28C are the same as those described above for heat-conducting plates 18A to 18C. Heat-conducting plate 28D extends further inward than heat-conducting plate 18D to reach heat-conducting plate 28C and connects to heat-conducting plate 28C. Heat-conducting plate 28E extends further inward than heat-conducting plate 18E to reach heat-conducting plate 28D and connects to heat-conducting plate 28D. Heat-conducting plate 28F extends further inward than heat-conducting plate 18F to reach heat-conducting plate 28E and connects to heat-conducting plate 28E. Heat-conducting plate 28G extends further inward than heat-conducting plate 18G to reach heat-conducting plate 28F and connects to heat-conducting plate 28F. As described above, heat-conducting plates 28D to 28G extend to the other heat-conducting plates 28. Regarding the additional heat-conducting plates 28D to 28G, their inner edges are connected to the other heat-conducting plates 28, and their inner and outer edges are supported and stabilized. The heat-conducting plates 28 do not intersect each other. With this configuration, each cylindrical battery 12 is in contact with at least two heat-conducting plates.

[0041] Figure 5 This is a diagram showing an example of a battery pack, or a portion thereof, 30, and is a schematic diagram showing a cross-section orthogonal to the central axis of the cylindrical battery 12. The cylindrical batteries 12 are arranged in a plane to form a layer. This layer is referred to as the arrangement layer 32. Figure 5 The example shown illustrates a structure with four arrangement layers 32A to 32D. When there is no need to distinguish between the four arrangement layers 32A to 32D, or when referred to collectively, A to D are omitted and simply referred to as arrangement layer 32. Furthermore, the direction in which the cylindrical battery 12 is arranged within one arrangement layer 32 is referred to as the battery arrangement direction. Figure 5 In the middle, the batteries are arranged in a left-right direction.

[0042] Layers 32A to 32D are each composed of the same number of cylindrical cells 12. Figure 5The example shown is an arrangement layer 32 consisting of four cylindrical batteries 12. Furthermore, arrangement layers consisting of n cylindrical batteries 12 and n+1 cylindrical batteries 12 can be alternately overlapped. The cylindrical batteries 12 belonging to adjacent arrangement layers 32 are arranged with their spacing staggered by half a pitch, entering the portion between the recesses formed by the sides of two adjacent cylindrical batteries 12 belonging to the opposite arrangement layer 32. Thus, a battery pack 34 is formed in which the cylindrical batteries 12 are arranged with their spacing staggered by half a pitch between adjacent arrangement layers 32.

[0043] A corrugated heat-conducting plate 36 is provided, extending to fill the gaps between the layers 32. The direction in which the heat-conducting plate 36 extends is the battery alignment direction. The heat-conducting plate 36 is formed in a corrugated shape and is made of a thermally conductive material, utilizing the material itself for heat conduction. The heat-conducting plate 36 can be formed, for example, from a metal plate, particularly an aluminum plate. In the direction of the central axis of the cylindrical battery 12, the dimensions of the cylindrical battery 12 and the heat-conducting plate 36 are approximately equal. The heat-conducting plate 36 has a portion that is bent along the side of the cylindrical battery 12. The heat-conducting plate 36 contacts the side of the cylindrical battery 12 locally and in a strip-shaped area extending along the length of the cylindrical battery 12 in the circumferential direction. The heat-conducting plate 36 can contact the cylindrical battery 12 directly, or it can contact it via an adhesive or the like. This contact improves the thermal conductivity compared to contact with air.

[0044] Heat sinks 38 and 40 are arranged in the battery arrangement direction and on both sides of the battery pack 34, and the end edges of both sides of each heat-conducting plate 36 are connected to the heat sinks 38 and 40. Heat generated in the cylindrical battery 12 is conducted through the heat-conducting plate 36 and flows to the heat sinks 38 and 40. The heat sinks 38 and 40 are made of thermally conductive materials such as metal, particularly aluminum, and dissipate heat conducted from the heat-conducting plate 36 from the side opposite to the surface of the cylindrical battery 12. Furthermore, fins can be provided on the surface of one or both of the two heat sinks 38 and 40 to promote heat dissipation. Additionally, a flow path can be formed inside one or both of the heat sinks 38 and 40, allowing fluid to flow through and dissipate heat to the fluid. Only one of the heat sinks 38 and 40 may be provided.

[0045] The waveforms of the heat-conducting plates 18 and 36 have portions that bend along the side of the cylindrical battery 12, but are not limited to this; they can be triangular wave shapes with plates arranged in an alternating pattern.

[0046] For 6 Figure 3 or Figure 4 The partial structures shown are combined to form battery pack 10, but they can also be used individually or in combination to form a battery pack of any number. For example, three of them can be combined to form a battery pack with the entire cross-section forming a semi-circular arc.

Claims

1. A partial configuration of a battery pack, wherein the partial configuration of the battery pack comprises: a battery group formed by a plurality of layers of cylindrical batteries arranged in a planar configuration, the cylindrical batteries belonging to adjacent layers being arranged with a half-pitch offset from each other between layers; a heat-conducting plate in contact with the side surface of the cylindrical battery arranged in a reverse surface, composed of a heat-conducting corrugated sheet material, and extending through the gaps between the cylindrical batteries in a direction of arrangement of the cylindrical batteries within the layer in a plane orthogonal to the central axis of the cylindrical battery, or a first intersecting direction intersecting the direction of arrangement, or a second intersecting direction intersecting both the direction of arrangement and the first intersecting direction; and a heat sink arranged on the side of the battery group, connected to the end edge of the heat-conducting plate, the cylindrical batteries are each in contact with at least two heat-conducting plates, the battery group has a first side and a second side in the direction of layer overlap, the number of cylindrical batteries belonging to each layer increasing one by one from the first side toward the second side, the heat sink is arranged at least on the second side, the heat-conducting plates include first direction heat-conducting plates extending in the first intersecting direction and second direction heat-conducting plates extending in the second intersecting direction, additional heat-conducting plates being added corresponding to the increase in the number of cylindrical batteries, each heat-conducting plate being connected to the heat sink on the second side, the heat-conducting plates are not in contact with each other, nor do they intersect.

2. The partial configuration of a battery pack according to claim 1, wherein the end edge of the additional heat-conducting plate toward the first side is not connected to other heat-conducting plates.

3. The partial configuration of a battery pack according to claim 1, wherein the end edge of the additional heat-conducting plate toward the first side is connected to other heat-conducting plates.

4. The partial configuration of a battery pack according to any one of claims 1 to 3, wherein the heat sink is also arranged on the first side on the basis of the second side, the heat-conducting plate traversing the layer closest to the first side being connected to the heat sink arranged on the first side.

5. A battery pack in which cylindrical batteries are arranged in a hexagonal configuration, the cylindrical batteries arranged in a hexagonal configuration being arranged in a plurality of concentric layers, wherein the battery pack has the partial configuration of a battery pack according to any one of claims 1 to 4 in portions corresponding to each side of the hexagonal configuration. ​

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