Battery cell and battery module

Abstract

A battery cell (100A) comprises: a battery element (110A); an exterior material (120A) that seals the battery element (110A); and an internal thermally conductive adhesive (150A) that is at least partially positioned between the battery element (110A) and the exterior material (120A).

Description

Battery cells and battery modules

[0001] This invention relates to battery cells and battery modules.

[0002] In recent years, various types of battery cells have been developed. A battery cell comprises a battery element and an outer casing that encloses the battery element.

[0003] Patent Document 1 describes a battery module. The battery module comprises a plurality of single cells and an upper holding member and a lower holding member located on both sides of the plurality of single cells in the stacking direction of the plurality of single cells. The uppermost single cell of the plurality of single cells and the upper holding member are bonded together by adhesive, and the lowermost single cell of the plurality of single cells and the lower holding member are bonded together by other adhesive.

[0004] Patent Document 2 describes a film-cased battery. The film-cased battery comprises a film casing material. A solid barrier material is provided on the inner surface of the ends of the film casing material from which the positive and negative terminals are drawn out.

[0005] Patent Document 3 describes a lithium-ion secondary battery. The lithium-ion secondary battery comprises a battery element, a battery case that houses the battery element, and a sealing plate provided at the upper opening of the battery case. A foamed resin sheet is placed between the lower part of the battery element and the battery case. Another foamed resin sheet is placed between the upper part of the battery element and the sealing plate.

[0006] Japanese Patent Publication No. 2019-053892, International Publication No. 2018 / 021550, Japanese Patent Publication No. 2002-231297

[0007] In battery cells, the battery elements may be cooled or heated. When cooling or heating the battery elements, it may be necessary to improve the heat exchange efficiency of the battery elements in order to facilitate cooling or heating.

[0008] One example of the object of the present invention is to improve the heat exchange efficiency of battery elements. Other objects of the present invention will become apparent from the description herein.

[0009] One aspect of the present invention is as follows: 1. A battery cell comprising: a battery element; an outer casing material that seals the battery element; and a heat conduction element at least partially located between the battery element and the outer casing material. 2. The battery cell according to 1, wherein the heat conduction element is bonded to the battery element and the outer casing material. 3. A battery module comprising: the battery cell according to 1 or 2; and a heat exchange element, wherein the heat conduction element is at least partially located between the battery element and a portion of the outer casing material located between the heat conduction element and the heat exchange element. 4. The battery module according to 3, further comprising another heat conduction element at least partially located between the portion of the outer casing material and the heat exchange element.

[0010] According to the above embodiment of the present invention, the heat exchange efficiency of the battery element can be improved.

[0011] This is an exploded top perspective view of the battery module according to the embodiment. This is a schematic cross-sectional view of the first virtual plane α shown in Figure 1. This is a perspective view of the battery cell according to the embodiment. This is a side view of the battery cell according to the embodiment with the outer film removed. This is a schematic cross-sectional view of the second virtual plane β shown in Figure 3.

[0012] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted where appropriate.

[0013] Figure 1 is an exploded top perspective view of the battery module 10A according to the embodiment. Figure 2 is a schematic cross-sectional view of the first virtual plane α shown in Figure 1.

[0014] Figures 1 and 2 show the X-axis, Y-axis, and Z-axis, respectively, for illustrative purposes. The X-axis indicates the front-to-back direction of the battery module 10A. The Y-axis is perpendicular to the X-axis. The Y-axis indicates the left-to-right direction of the battery module 10A. The Z-axis is perpendicular to both the X-axis and Y-axis. The Z-axis indicates the up-to-down direction of the battery module 10A. The relationship between the X-axis, Y-axis, and Z-axis and the front-to-back, left-to-right, and up-to-down directions of the battery module 10A is not limited to the examples given above. The arrows on the X-axis, Y-axis, and Z-axis point forward, left, and upward, respectively, of the battery module 10A. In Figure 2, the white circle with a black dot indicating the X-axis indicates that the X-axis arrow is pointing towards the viewer on the page.

[0015] Unless otherwise specified, the +X side refers to the tip of the X-axis arrow, and the -X side refers to the base end of the X-axis arrow. Unless otherwise specified, the +Y side refers to the tip of the Y-axis arrow, and the -Y side refers to the base end of the Y-axis arrow. Unless otherwise specified, the +Z side refers to the tip of the Z-axis arrow, and the -Z side refers to the base end of the Z-axis arrow.

[0016] As shown in Figure 1, the battery module 10A comprises a plurality of battery cells 100A, a plurality of compression pads 200, a first voltage detection device 300, a second voltage detection device 400, and a housing 500.

[0017] As shown in Figure 1, the multiple battery cells 100A and the multiple compression pads 200 are stacked alternately in the Y direction. Hereafter, unless otherwise specified, the stack of battery cells 100A refers to the multiple battery cells 100A and the multiple compression pads 200 stacked alternately in the Y direction. The longitudinal direction of each battery cell 100A is oriented in the X direction. The short direction of each battery cell 100A is oriented in the Z direction. The thickness direction of each battery cell 100A is oriented in the Y direction. The shape of each battery cell 100A is not limited to this example.

[0018] As shown in Figures 1 and 2, each battery cell 100A includes a battery element 110A, an outer casing 120A, a positive electrode terminal 132A, a negative electrode terminal 134A, and an internal thermal conductive adhesive 150A. Hereinafter, the internal thermal conductive adhesive 150A may simply be referred to as the internal adhesive 150A. The internal adhesive 150A is a thermal conductive element.

[0019] In one example, the battery element 110A includes a plurality of positive electrodes and a plurality of negative electrodes stacked alternately in the Y direction, and a separator located between adjacent positive electrodes and negative electrodes in the Y direction. In Figure 2, the outline of the cross-section of the battery element 110A perpendicular to the X direction is shown as having a substantially rectangular shape including a pair of short sides substantially parallel to the Y direction and a pair of long sides substantially parallel to the Z direction. The structure of the battery element 110A is not limited to the example described above.

[0020] The outer casing material 120A seals the battery element 110A and the electrolyte. In the example shown in Figure 2, the outer casing material 120A includes a first laminate film 122A and a second laminate film 124A. The outer casing material 120A encloses the battery element 110A with the first laminate film 122A covering the +Y side portion of the battery element 110A and the second laminate film 124A covering the -Y side portion of the battery element 110A. In the example shown in Figure 2, the portions of the first laminate film 122A and the second laminate film 124A that extend from the +Z side portion of the battery element 110A are joined to each other, for example, by heat welding. In the example shown in Figure 2, the portions of the first laminate film 122A and the second laminate film 124A that are drawn out from the -Z side portion of the battery cell 100A are joined to each other, for example, by heat fusion.

[0021] The structure of the outer casing 120A is not limited to the examples shown in Figures 1 and 2. In one example, the outer casing 120A may have a single laminate film that is folded over on one of the +Z side and -Z side portions of the battery cell 100A. In this example, the portions of the single laminate film that are pulled out from the other side of the +Z side and -Z side portion of the battery cell 100A are joined together, for example, by heat fusion. The battery element 110A can also be wrapped with a single laminate film.

[0022] The positive terminal 132A is electrically connected to the positive terminal of the battery element 110A. The positive terminal 132A is drawn out from one of the two sides in the X direction of the casing material 120A. The negative terminal 134A is electrically connected to the negative terminal of the battery element 110A. The negative terminal 134A is drawn out from the other of the two sides in the X direction of the casing material 120A. However, the structure of each battery cell 100A is not limited to this example.

[0023] Each battery cell 100A may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion corresponding to the separator. All-solid-state batteries do not contain electrolyte. Hereafter, unless otherwise specified, each battery cell 100A will be described as a battery cell containing electrolyte.

[0024] Multiple battery cells 100A are electrically connected by a combination of series and parallel connections. Specifically, as shown in Figure 1, a group of cells including at least two adjacent battery cells 100A connected in parallel in the Y direction is stacked in the Y direction and connected in series. On the +X side of the stack of battery cells 100A, a positive terminal 132A drawn from a battery cell 100A of one of the parallel-connected cell groups and a negative terminal 134A drawn from a battery cell 100A of another parallel-connected cell group are electrically connected to each other, forming a terminal group 136A including the positive terminal 132A and the negative terminal 134A. The positive terminal 132A and the negative terminal 134A in the terminal group 136A are joined to each other, for example, by laser welding. A terminal group 136A is similarly located on the -X side of the stack of battery cells 100A. Therefore, multiple cell groups are connected in series from the cell group located on one end of the stack of battery cells 100A in the Y direction to the cell group located on the other end of the stack of battery cells 100A in the Y direction. Hereafter, unless otherwise specified, the +X side terminal group 136A refers to the terminal group 136A located on the +X side of the stack of battery cells 100A, and the -X side terminal group 136A refers to the terminal group 136A located on the -X side of the stack of battery cells 100A.

[0025] The electrical connections of multiple battery cells 100A are not limited to the examples described above. For example, a stack of battery cells 100A may be formed by connecting single battery cells 100A in series.

[0026] The first voltage detection device 300 detects the voltages of multiple +X-side terminal groups 136A. The first voltage detection device 300 includes a first protector 310, multiple first voltage detection terminals 320, multiple first voltage detection lines 330, a first connector 340, and a first busbar 350.

[0027] The first protector 310 covers the +X side portion of the laminate of the battery cell 100A. The first protector 310 is an insulator such as resin. The first protector 310 defines a plurality of first openings 312. Each of the plurality of +X side terminal groups 136A is exposed toward the +X side through each of the plurality of first openings 312.

[0028] Each of the multiple first voltage detection terminals 320 is located on the +X side of each of the multiple +X-side terminal groups 136A. Each first voltage detection terminal 320 is, for example, a conductive material such as metal. The -X side of each first voltage detection terminal 320 and the +X side of each +X-side terminal group 136A are joined to each other by a joining method such as laser welding. Therefore, each first voltage detection terminal 320 and each +X-side terminal group 136A are electrically connected to each other. Thus, the first voltage detection device 300 can detect the voltage of each +X-side terminal group 136A using each first voltage detection terminal 320. The multiple first voltage detection terminals 320 are integrally held by the first protector 310. Therefore, by installing the first protector 310 at an appropriate position relative to the stack of battery cells 100A, each of the multiple first voltage detection terminals 320 can be positioned at an appropriate position relative to each of the multiple +X-side terminal groups 136A.

[0029] One end of each first voltage detection line 330 is electrically connected to each first voltage detection terminal 320. The other end of each first voltage detection line 330 is electrically connected to the first connector 340. Therefore, the multiple first voltage detection terminals 320 and the first connector 340 are electrically connected to each other via the multiple first voltage detection lines 330. Each first voltage detection line 330 is routed between one end of each first voltage detection line 330 and the other end of each first voltage detection line 330 via the first protector 310.

[0030] The first busbar 350 is located at the +Y side end of the first protector 310. The first busbar 350 is electrically connected to the positive terminal 132A that is drawn out to the +X side from the battery cell 100A of the cell group located at the +Y side end of the stack of battery cells 100A. The first busbar 350 functions as an external terminal for electrically connecting the battery module 10A to external devices such as other battery modules.

[0031] The second voltage detection device 400 detects the voltages of multiple -X-side terminal groups 136A. The second voltage detection device 400 includes a second protector 410, multiple second voltage detection terminals 420, multiple second voltage detection lines 430, a second connector 440, and a second busbar 450.

[0032] The second protector 410 covers the -X side portion of the laminate of the battery cell 100A. The second protector 410 is an insulator such as resin. The second protector 410 defines a plurality of second openings 412. Each of the plurality of -X side terminal groups 136A is exposed toward the -X side through each of the plurality of second openings 412.

[0033] Each of the multiple second voltage detection terminals 420 is located on the -X side of each of the multiple -X side terminal groups 136A. Each second voltage detection terminal 420 is made of a conductive material such as metal. The +X side of each second voltage detection terminal 420 and the -X side of each -X side terminal group 136A are joined to each other by a joining method such as laser welding. Therefore, each second voltage detection terminal 420 and each -X side terminal group 136A are electrically connected to each other. Thus, the second voltage detection device 400 can detect the voltage of each -X side terminal group 136A using each second voltage detection terminal 420. The multiple second voltage detection terminals 420 are integrally held by the second protector 410. Therefore, by installing the second protector 410 at an appropriate position relative to the stack of battery cells 100A, each of the multiple second voltage detection terminals 420 can be positioned at an appropriate position relative to each of the multiple -X side terminal groups 136A.

[0034] Each second voltage detection line 430 has one end that is electrically connected to each second voltage detection terminal 420. Each second voltage detection line 430 has one end that is electrically connected to each second connector 440. Therefore, the multiple second voltage detection terminals 420 and the second connector 440 are electrically connected to each other via the multiple second voltage detection lines 430. Each second voltage detection line 430 is routed between one end of the second voltage detection line 430 and the other end of the second voltage detection line 430 via a second protector 410.

[0035] The second bus bar 450 is disposed at the -Y side end of the second protector 410. The second bus bar 450 is electrically connected to the negative electrode terminal 134A drawn from the battery cell 100A of the cell group located at the -Y side end of the stack of battery cells 100A. The second bus bar 450 functions as an external terminal for electrically connecting the battery module 10A to an external device such as another battery module.

[0036] In the example shown in FIG. 1, the positive electrode terminals 132A at the ends of the plurality of cell groups connected in series are drawn from the battery cells 100A of the cell group located at the +Y side end of the stack of battery cells 100A toward the +X side, and the negative electrode terminals 134A at the ends of the plurality of cell groups connected in series are drawn from the battery cells 100A of the cell group located at the -Y side end of the stack of battery cells 100A toward the -X side. Therefore, the first bus bar 350 is disposed on the +X side and the +Y side with respect to the stack of battery cells 100A, and the second bus bar 450 is disposed on the -X side and the -Y side with respect to the stack of battery cells 100A. However, the arrangement of the positive electrode terminals 132A and the negative electrode terminals 134A at the ends of the plurality of cell groups connected in series may vary depending on the number of battery cells 100A included in the stack of battery cells 100A. For example, the positive electrode terminals 132A at the ends of the plurality of cell groups connected in series may be drawn from the battery cells 100A of the cell group located at the +Y side end of the stack of battery cells 100A toward the +X side, and the negative electrode terminals 134A at the ends of the plurality of cell groups connected in series may be drawn from the battery cells 100A of the cell group located at the -Y side end of the stack of battery cells 100A toward the +X side. In this case, the first bus bar 350 is disposed on the +X side and the +Y side with respect to the stack of battery cells 100A, and the second bus bar 450 is disposed on the +X side and the -Y side with respect to the stack of battery cells 100A.

[0037] The housing 500 houses the stack of battery cells 100A. The housing 500 has a first plate 510, a second plate 520, a third plate 530, a fourth plate 540, a fifth plate 550, and a sixth plate 560. Each plate is, for example, a metal plate.

[0038] The first plate 510 covers the +X side portion of the stacked body of the battery cells 100A with the first voltage detection device 300 positioned between the stacked body of the battery cells 100A and the first plate 510. The second plate 520 covers the -X side portion of the stacked body of the battery cells 100A with the second voltage detection device 400 positioned between the stacked body of the battery cells 100A and the second plate 520. The third plate 530 covers the +Y side portion of the stacked body of the battery cells 100A. The fourth plate 540 covers the -Y side portion of the stacked body of the battery cells 100A. The fifth plate 550 covers the +Z side portion of the stacked body of the battery cells 100A with a plurality of structural adhesives 610 positioned between the stacked body of the battery cells 100A and the fifth plate 550. In the example shown in FIG. 1, the plurality of structural adhesives 610 extend in the Y direction. The arrangement of the structural adhesives 610 is not limited to the example shown in FIG. 1. The stacked body of the battery cells 100A and the fifth plate 550 are adhered to each other via the plurality of structural adhesives 610. The sixth plate 560 covers the -Z side portion of the stacked body of the battery cells 100A with an external heat conductive adhesive 620 positioned between the stacked body of the battery cells 100A and the sixth plate 560. The stacked body of the battery cells 100A and the sixth plate 560 are adhered to each other via the external heat conductive adhesive 620. The stacked body of the battery cells 100A and the sixth plate 560 are thermally coupled to each other via the external heat conductive adhesive 620. Hereinafter, the external heat conductive adhesive 620 may also be simply referred to as the external adhesive 620. The external adhesive 620 is a heat conduction element.

[0039] Referring to FIGS. 1 and 2, the battery module 10A will be further described.

[0040] Hereinafter, as necessary, the -Z side outer surface of the battery element 110A is referred to as the outer bottom surface of the battery element 110A, the portion of the exterior material 120A that covers the outer bottom surface of the battery element 110A is referred to as the bottom portion of the exterior material 120A, the +Z side surface of the bottom portion of the exterior material 120A is referred to as the inner bottom surface of the exterior material 120A, the -Z side surface of the bottom portion of the exterior material 120A is referred to as the outer bottom surface of the exterior material 120A, and the +Z side surface of the sixth plate 560 is referred to as the inner bottom surface of the sixth plate 560.

[0041] As shown in Figure 2, the internal adhesive 150A is at least partially located between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A. The internal adhesive 150A adheres the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A. Therefore, the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A are physically joined to each other via the internal adhesive 150A. Thus, displacement of the battery element 110A and the casing material 120A due to external impacts to the battery cell 100A can be suppressed. Furthermore, the internal adhesive 150A can more easily distribute the load on the bottom of the casing material 120A due to the weight of the battery element 110A, thereby suppressing damage to the bottom of the casing material 120A due to the weight of the battery element 110A. In addition, the internal adhesive 150A may function as a reinforcing member to improve the strength of the battery element 110A.

[0042] The internal thermal conductive adhesive 150A is a heat transfer element having, for example, a thermal conductivity of 1.0 W / m·K or higher. In one example, the internal adhesive 150A is a fluorinated elastomer having a fluorinated polyether skeleton. Alternatively, the internal adhesive 150A may be a silicone-based elastomer adhesive with a siloxane bond as its main skeleton, and specifically, it may be polydimethylsiloxane (PDMS). Alternatively, the internal adhesive 150A may be a combination of these materials as exemplified. When the internal adhesive 150A is cured, the outer bottom surface of the battery element 110A and the inner bottom surface of the exterior material 120A are bonded to each other. However, the state of the internal adhesive 150A is not particularly limited as long as the outer bottom surface of the battery element 110A and the inner bottom surface of the exterior material 120A are bonded to each other, and may be in an elastic state, such as a gel state. The +Z side of the internal adhesive 150A and the outer bottom surface of the battery element 110A are in contact with each other, and the -Z side of the internal adhesive 150A and the inner bottom surface of the casing material 120A are in contact with each other. Therefore, the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A are thermally bonded to each other via the internal adhesive 150A. Consequently, the heat exchange efficiency between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A can be improved by the internal adhesive 150A. Furthermore, the position of the internal adhesive 150A between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A makes it difficult for the electrolyte to enter the gap between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A. The thermal conductivity of the electrolyte is lower than that of the internal adhesive 150A. Therefore, compared to the case where the gap between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A is filled with electrolyte, the heat exchange efficiency between the outer bottom surface of the battery element 110A and the inner bottom surface of the casing material 120A can be improved by the internal adhesive 150A.

[0043] The sixth plate 560 serves as a heat exchange element for cooling and / or heating the stack of battery cells 100A. For example, the sixth plate 560 can be adjusted to an appropriate temperature by a cooler and a heater provided outside the battery module 10A. For example, if the temperature of the stack of battery cells 100A is higher than the appropriate temperature for the operation of the battery module 10A due to the heat generated by at least one battery cell 100A, the sixth plate 560 operates to cool the stack of battery cells 100A by being cooled by a cooler provided outside the battery module 10A. Alternatively, for example, if the battery module 10A is used in a relatively low-temperature environment and the temperature of the stack of battery cells 100A is lower than the appropriate temperature for the operation of the battery module 10A, the sixth plate 560 operates to heat the stack of battery cells 100A by being heated by a heater provided outside the battery module 10A. In other examples, the sixth plate 560 itself may be at least one of the cooler and the heater. Hereafter, unless otherwise specified, the sixth plate 560 will be described as being cooled by a cooling body provided outside the battery module 10A and operating as a cooling body for cooling the stack of battery cells 100A.

[0044] As shown in Figure 1, the external adhesive 620 is at least partially located between the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560. The external adhesive 620 adheres the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560. Therefore, the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560 are physically joined to each other via the external adhesive 620. Consequently, displacement of the battery cells 100A and the sixth plate 560 due to external impacts to the battery module 10A can be suppressed.

[0045] The external thermal conductive adhesive 620 is, for example, a heat transfer element having a thermal conductivity of 1.0 W / m·K or higher. In one example, the external adhesive 620 is a silicone adhesive, a urethane adhesive, or an acrylic adhesive. When the external adhesive 620 is cured, the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560 are bonded to each other. However, the state of the external adhesive 620 is not particularly limited as long as the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560 are bonded to each other, and may be in an elastic state such as a gel state. The +Z side of the external adhesive 620 and the outer bottom surface of the exterior material 120A are in contact with each other, and the -Z side of the external adhesive 620 and the inner bottom surface of the sixth plate 560 are in contact with each other. Therefore, the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560 are thermally bonded to each other via the external adhesive 620. Therefore, the heat exchange efficiency between the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560 can be improved by the sixth plate 560.

[0046] As can be seen from Figures 1 and 2, in Embodiment 1, the internal adhesive 150A is positioned at least partially between the outer bottom surface of the battery element 110A and the inner bottom surface of the sixth plate 560, and the external adhesive 620 is positioned at least partially between the outer bottom surface of the exterior material 120A and the inner bottom surface of the sixth plate 560. The outer bottom surface of the battery element 110A and the inner bottom surface of the sixth plate 560 are thermally bonded to each other via the internal adhesive 150A, the bottom surface of the exterior material 120A, and the external adhesive 620. Therefore, the heat exchange efficiency of the battery element 110A can be improved compared to the case where the internal adhesive 150A is not provided. Thus, in Embodiment 1, the battery element 110A can be cooled more easily by the sixth plate 560 compared to the case where the internal adhesive 150A is not provided.

[0047] Figure 3 is a perspective view of the battery cell 100B according to Embodiment 2. Figure 4 is a side view of the battery cell 100B according to the embodiment with the outer casing material 140B removed. Figure 5 is a schematic cross-sectional view of the second virtual plane β shown in Figure 3. The battery cell 100B according to Embodiment 2 is the same as the battery cell 100A according to Embodiment 1, except for the following points.

[0048] The second virtual plane β shown in Figures 3 and 5 is a plane perpendicular to the X direction at approximately the center of the battery cell 100B in the X direction according to the embodiment. For illustrative purposes, the ratio of the Y direction to the Z direction of the battery cell 100B shown in Figure 5 is larger than the ratio of the Y direction to the Z direction of the battery cell 100B shown in Figure 3.

[0049] As shown in Figures 3 to 5, the battery cell 100B according to this embodiment comprises a plurality of battery elements 110B, a pair of terminals 120B, a pair of cover materials 130B, an outer casing material 140B, and an internal thermal conductive adhesive 150B. Hereinafter, the internal thermal conductive adhesive 150B may simply be referred to as the internal adhesive 150B. The internal adhesive 150B is a thermal conductive element.

[0050] In the example shown in Figure 5, multiple battery elements 110B overlap each other in the Y direction. Hereafter, if necessary, multiple battery elements 110B overlapping each other in the Y direction will be referred to as a single unit, a laminate 111B. Each battery element 110B has a roughly rectangular parallelepiped shape. Specifically, when viewed from the X direction, each battery element 110B has a longitudinal direction and a transverse direction perpendicular to the X direction. When viewed from the X direction, the longitudinal direction of each battery element 110B is oriented in the Z direction. When viewed from the X direction, the transverse direction of each battery element 110B is oriented in the Y direction. In the examples shown in Figures 3 and 5, when viewed from the X direction, the laminate 111B has a longitudinal direction and a transverse direction perpendicular to the X direction, similar to each battery element 110B. The number of battery elements 110B included in the battery cell 100B is not limited to the example shown in Figure 5. For example, the battery cell 100B may have only one battery element 110B, two battery elements 110B, or four or more battery elements 110B.

[0051] As shown in Figure 5, each battery element 110B has a plurality of positive electrodes 112B, a plurality of negative electrodes 114B, and a separator 116B. In each battery element 110B, the plurality of positive electrodes 112B and the plurality of negative electrodes 114B are arranged alternately in the Y direction. The area of ​​each negative electrode 114B perpendicular to the Y direction is larger than the area of ​​each positive electrode 112B perpendicular to the Y direction. In the example shown in Figure 5, the dimension of each negative electrode 114B in the Z direction is larger than the dimension of each positive electrode 112B in the Z direction. As shown in Figure 5, viewed from the X direction, the separator 116B includes a zigzag portion 117B and a surrounding portion 118B. Viewed from the X direction, the zigzag portion 117B is alternately folded at the +Z side folded portion and the -Z side folded portion of the zigzag portion 117B. Viewed from the X direction, the zigzag portion 117B separates the adjacent positive and negative electrodes 112B and 114B in the Y direction, with the folded portion on the +Z side of the zigzag portion 117B covering the +Z end of the positive electrode 112B, and the folded portion on the -Z side of the zigzag portion 117B covering the -Z end of the negative electrode 114B. Viewed from the X direction, the surrounding portion 118B surrounds the alternating positive and negative electrodes 112B and 114B in the Y direction, as well as the zigzag portion 117B.

[0052] The structure of separator 116B is not limited to the structure shown in Figure 5. For example, separator 116B may not include the surrounding portion 118B and may include only the zigzag portion 117B. Alternatively, the battery element 110B may include a plurality of substantially sheet-shaped separators 116B perpendicular to the Y direction instead of the separator 116B shown in Figure 5. When the battery element 110B includes a plurality of substantially sheet-shaped separators 116B perpendicular to the Y direction, the plurality of positive electrodes 112B, a plurality of negative electrodes 114B, and a plurality of separators 116B overlap in the Y direction, with each separator 116B separating adjacent positive electrodes 112B and negative electrodes 114B in the Y direction. Alternatively, the positive electrodes 112B, negative electrodes 114B, and separators 116B may be wound so that the separators 116B are positioned between the positive electrodes 112B and negative electrodes 114B. In one example, the positive electrode 112B, the negative electrode 114B, and the separator 116B are wound together with one side of both the positive electrode 112B and the negative electrode 114B covered by the separator 116B. In another example, a laminate containing multiple unit laminates, each containing the positive electrode 112B, the separator 116B, and the negative electrode 114B in this order, may be wound together. However, the winding structure of the positive electrode 112B, the negative electrode 114B, and the separator 116B is not limited to these examples.

[0053] As shown in Figure 4, the pair of terminals 120B are located on both sides of the laminate 111B in the X direction. The terminal 120B on the -X side and the positive electrode 112B of the laminate 111B are electrically connected to each other via the leading positive electrode current collector 113B. Therefore, in this embodiment, the terminal 120B on the -X side is the positive electrode terminal. The leading positive electrode current collector 113B is drawn out from the laminate 111B toward the -X side. In one example, the leading positive electrode current collector 113B is integrated with the positive electrode current collector that constitutes the positive electrode 112B. The terminal 120B on the +X side and the negative electrode 114B of the laminate 111B are electrically connected to each other via the leading negative electrode current collector 115B. Therefore, in this embodiment, the terminal 120B on the +X side is the negative electrode terminal. The leading negative electrode current collector 115B is drawn out from the laminate 111B toward the +X side. In one example, the leading negative electrode current collector 115B is integrated with the negative electrode current collector that constitutes the negative electrode 114B. The terminal 120B on the -X side may be the negative electrode terminal, and the terminal 120B on the +X side may be the positive electrode terminal.

[0054] As shown in Figure 3, the pair of cover members 130B are located on both sides of the laminate 111B in the X direction. Each cover member 130B is, for example, made of resin. As shown in Figure 3, when viewed from the X direction, each cover member 130B has a substantially rectangular shape with a pair of short sides parallel to the Y direction and a pair of long sides parallel to the Z direction. The -X side terminal 120B protrudes at least partially toward the -X side from the -X side surface of the -X side cover member 130B, with the -X side cover member 130B covering the -X side end face of the laminate 111B. The +X side terminal 120B protrudes at least partially toward the +X side from the +X side surface of the +X side cover member 130B, with the +X side cover member 130B covering the +X side end face of the laminate 111B.

[0055] The outer packaging material 140B seals the laminate 111B and the electrolyte. In this embodiment, the outer packaging material 140B is a flexible laminate film. As shown in Figures 3 and 5, the outer packaging material 140B has a winding portion 142B and an unwinding portion 144B. The winding portion 142B is wound around the laminate 111B and the pair of lid materials 130B in the X direction. The outer circumferential surface of the lid material 130B on the -X side in the X direction and the inner circumferential surface of the -X side end of the winding portion 142B in the X direction are joined to each other by a joining method such as heat fusion. Thus, a sealing portion is formed by the -X side lid material 130B and the -X side end of the winding portion 142B. The outer circumferential surface of the lid material 130B on the +X side in the X direction and the inner circumferential surface of the +X side end of the winding portion 142B in the X direction are joined to each other by a joining method such as heat fusion. Therefore, a sealing portion is formed by the +X side cover material 130B and the +X side end of the winding portion 142B. As shown in Figure 5, the pull-out portion 144B includes a first pull-out portion 145B and a second pull-out portion 146B. The first pull-out portion 145B is pulled out from one end of the winding portion 142B around the X direction, and the second pull-out portion 146B is pulled out from the other end of the winding portion 142B around the X direction. The surfaces of the first pull-out portion 145B and the second pull-out portion 146B that are in contact with each other are joined to each other by a joining method such as heat fusion. Therefore, a sealing portion is formed by the first pull-out portion 145B and the second pull-out portion 146B. In the example shown in Figures 3 and 5, when viewed from the X direction, the pull-out portion 144B is pulled out from the +Y side and +Z side corner of the laminate 111B and bent toward the +Z side outer surface of the winding portion 142B. However, the way in which the pull-out portion 144B is pulled out is not limited to the examples shown in Figures 3 and 5.

[0056] In the battery cell 100B according to this embodiment, the pair of lid materials 130B and outer casing material 140B seal the space enclosed by the winding portion 142B between the pair of lid materials 130B. The laminate 111B is located inside the space sealed by the pair of lid materials 130B and outer casing material 140B. The battery cell 100B according to this embodiment contains an electrolyte inside the space sealed by the pair of lid materials 130B and outer casing material 140B. However, the battery cell 100B may be an all-solid-state battery. In an all-solid-state battery, a solid electrolyte layer is provided in the portion corresponding to the separator 116B. An all-solid-state battery does not contain an electrolyte. Hereinafter, unless otherwise specified, the battery cell 100B will be described as a battery cell containing an electrolyte.

[0057] Hereafter, as necessary, the -Z side outer surface of the laminate 111B will be referred to as the outer bottom surface of the laminate 111B, the portion of the winding portion 142B that covers the outer bottom surface of the laminate 111B will be referred to as the bottom of the winding portion 142B, the +Z side of the bottom of the winding portion 142B will be referred to as the inner bottom surface of the winding portion 142B, and the -Z side of the bottom of the winding portion 142B will be referred to as the outer bottom surface of the winding portion 142B.

[0058] As shown in Figure 5, the internal adhesive 150B is at least partially located between the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B. The internal adhesive 150B adheres the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B. Therefore, the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B are physically joined to each other via the internal adhesive 150B. Consequently, displacement of multiple battery elements 110B within the laminate 111B and displacement of the laminate 111B and the outer material 140B due to external impacts to the battery cell 100B can be suppressed. Furthermore, the internal adhesive 150B can more easily distribute the load on the bottom of the winding portion 142B due to the weight of the laminate 111B, thereby suppressing damage to the bottom of the winding portion 142B due to the weight of the laminate 111B. Furthermore, the internal adhesive 150B may function as a reinforcing member to improve the strength of the laminate 111B.

[0059] The internal thermal conductive adhesive 150B is, for example, a heat transfer element having a thermal conductivity of 1.0 W / m·K or higher. In one example, the internal adhesive 150B is a fluorinated elastomer having a fluorinated polyether skeleton. Alternatively, the internal adhesive 150B may be a silicone-based elastomer adhesive with a siloxane bond as its main skeleton, and specifically, it may be polydimethylsiloxane (PDMS). Alternatively, the internal adhesive 150B may be a combination of these materials as exemplified. In the cured state of the internal adhesive 150B, the outer bottom surface of the laminate 111B and the inner bottom surface of the wrapped portion 142B are bonded to each other. However, the state of the internal adhesive 150B is not particularly limited as long as the outer bottom surface of the laminate 111B and the inner bottom surface of the wrapped portion 142B are bonded to each other, and may be in an elastic state such as a gel state. The +Z side of the internal adhesive 150B and the outer bottom surface of the laminate 111B are in contact with each other, and the -Z side of the internal adhesive 150B and the inner bottom surface of the winding portion 142B are in contact with each other. Therefore, the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B are thermally bonded to each other via the internal adhesive 150B. Consequently, the heat exchange efficiency between the outer bottom surface of the laminate 111B and the inner bottom surface of the exterior material 140B can be improved by the internal adhesive 150B. Furthermore, the position of the internal adhesive 150B between the outer bottom surface of the laminate 111B and the inner bottom surface of the exterior material 140B makes it difficult for the electrolyte to enter the gap between the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B. The thermal conductivity of the electrolyte is lower than that of the internal adhesive 150B. Therefore, compared to the case where the gap between the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B is filled with electrolyte, the heat exchange efficiency between the outer bottom surface of the laminate 111B and the inner bottom surface of the winding portion 142B can be improved by the internal adhesive 150B.

[0060] The battery cell 100B according to Embodiment 2 is applicable to a battery module comprising a plurality of battery cells 100B, similar to the battery cell 100A according to Embodiment 1. In the battery module according to Embodiment 2, the plurality of battery cells 100B according to Embodiment 2 are stacked in the Y direction, similar to the plurality of battery cells 100A according to Embodiment 1, and are electrically connected to each other in series, parallel, or a combination of series and parallel. Hereinafter, the battery module according to Embodiment 2 will be described assuming that the plurality of battery cells 100B according to Embodiment 2 are housed in the housing 500 shown in Figure 1.

[0061] In Embodiment 2, as in Embodiment 1, the external adhesive 620 is at least partially positioned between the outer bottom surface of the winding portion 142B and the inner bottom surface of the sixth plate 560. The external adhesive 620 adheres the outer bottom surface of the winding portion 142B and the inner bottom surface of the sixth plate 560. Therefore, the outer bottom surface of the winding portion 142B and the inner bottom surface of the sixth plate 560 are physically joined to each other via the external adhesive 620. Consequently, displacement of the battery cell 100B and the sixth plate 560 due to external impacts to the battery module can be suppressed.

[0062] In Embodiment 2, the external thermal conductive adhesive 620 also serves as a heat transfer element. The +Z side of the external adhesive 620 and the outer bottom surface of the winding portion 142B are in contact with each other, and the -Z side of the external adhesive 620 and the inner bottom surface of the sixth plate 560 are in contact with each other. Therefore, the outer bottom surface of the winding portion 142B and the inner bottom surface of the sixth plate 560 are thermally bonded to each other via the external adhesive 620. Consequently, the heat exchange efficiency between the outer bottom surface of the winding portion 142B and the inner bottom surface of the sixth plate 560 can be improved by the external adhesive 620.

[0063] In Embodiment 2, the internal adhesive 150B is positioned at least partially between the outer bottom surface of the laminate 111B and the inner bottom surface of the sixth plate 560, and the external adhesive 620 is positioned at least partially between the outer bottom surface of the wrap-around portion 142B and the inner bottom surface of the sixth plate 560. The outer bottom surface of the laminate 111B and the inner bottom surface of the sixth plate 560 are thermally bonded to each other via the internal adhesive 150B, the bottom of the wrap-around portion 142B, and the external adhesive 620. Therefore, the heat exchange efficiency of the laminate 111B can be improved compared to the case where the internal adhesive 150B is not provided. Thus, in Embodiment 2, the laminate 111B can be cooled more easily by the sixth plate 560 compared to the case where the internal adhesive 150B is not provided.

[0064] The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can also be adopted.

[0065] For example, in Embodiment 2, the terminal 120B electrically connected to the positive electrode 112B and the terminal 120B electrically connected to the negative electrode 114B are located on both sides of the battery element 110B in the X direction. However, both the terminal 120B electrically connected to the positive electrode 112B and the terminal 120B electrically connected to the negative electrode 114B may be located on the same side of the battery element 110B, either the +X side or the -X side.

[0066] One aspect of the present invention will be described based on Example 1, Example 2, Comparative Example 1, and Comparative Example 2. The present invention is not limited to the following examples.

[0067] The battery cell according to Example 1, similar to the battery cell 100A according to Embodiment 1, includes a battery element, an outer casing material enclosing the battery element, a positive electrode terminal drawn out from the outer casing material, a negative electrode terminal drawn out from the outer casing material, and an internal thermal conductive adhesive for bonding the battery element and the outer casing material. The battery cell according to Example 1 corresponds to the battery cell 100A according to Embodiment 1. The battery element according to Example 1 corresponds to the battery element 110A according to Embodiment 1. The outer casing material according to Example 1 corresponds to the outer casing material 120A according to Embodiment 1. The positive electrode terminal according to Example 1 corresponds to the positive electrode terminal 132A according to Embodiment 1. The negative electrode terminal according to Example 1 corresponds to the negative electrode terminal 134A according to Embodiment 1. The internal thermal conductive adhesive according to Example 1 corresponds to the internal thermal conductive adhesive 150A according to Embodiment 1.

[0068] In Example 1, a cooling plate and an external thermal conductive adhesive were prepared. An internal thermal conductive adhesive was positioned between the battery element and a portion of the exterior material, and an external thermal conductive adhesive was positioned between the portion of the exterior material and the cooling plate. The battery cell was then cooled by the cooling plate. The external thermal conductive adhesive in Example 1 corresponds to the external adhesive 620 in Embodiment 1. The cooling plate in Example 1 corresponds to the sixth plate 560 in Embodiment 1.

[0069] The battery cell according to Comparative Example 1 is the same as the battery cell according to Example 1, except that it does not have an internal thermally conductive adhesive.

[0070] In Comparative Example 1, an external thermal conductive adhesive was positioned between a portion of the exterior material and the cooling plate, and the battery cell was cooled by the cooling plate.

[0071] The battery cell according to Example 2, similar to the battery cell 100B according to Embodiment 2, includes a battery element, terminals electrically connected to the battery element, a cover material covering the battery element, an outer covering material wrapped around the battery element and the cover material, and an internally thermally conductive adhesive for bonding the battery element and the outer covering material. The battery cell according to Example 2 corresponds to the battery cell 100B according to Embodiment 2. The battery element according to Example 2 corresponds to the battery element 110B according to Embodiment 2. The terminal according to Example 2 corresponds to the terminal 120B according to Embodiment 2. The cover material according to Example 2 corresponds to the cover material 130B according to Embodiment 2. The outer covering material according to Example 2 corresponds to the outer covering material 140B according to Embodiment 2. The internally thermally conductive adhesive according to Example 2 corresponds to the internally thermally conductive adhesive 150B according to Embodiment 2.

[0072] In Example 2, similar to Example 1, an internal thermal conductive adhesive was positioned between the battery element and a portion of the exterior material, and an external thermal conductive adhesive was positioned between the portion of the exterior material and the cooling plate, and the battery cell was cooled by the cooling plate.

[0073] The battery cell according to Comparative Example 2 is the same as the battery cell according to Example 2, except that it does not have an internal thermally conductive adhesive.

[0074] In Comparative Example 2, the battery cell was cooled by the cooling plate with an external thermal conductive adhesive positioned between a portion of the exterior material and the cooling plate.

[0075] To evaluate the battery cells of Example 1, Comparative Example 1, Example 2, and Comparative Example 2, a reference example battery cell was prepared. The reference example battery cell is the same as the battery cell of Example 1, except that it does not have an internal thermal conductive adhesive. In the reference example, the battery cell was cooled by air cooling without using a cooling plate or an external thermal conductive adhesive.

[0076] Table 1 shows the simulation results of the cooling improvement rates for 1C charge / discharge, 2C charge / discharge, and 5C charge / discharge in the battery cells according to Example 1, Comparative Example 1, Example 2, and Comparative Example 2 with respect to the battery cell according to the reference example. The numerical values (unit: %) in the column of "1C charge / discharge" in Table 1, the numerical values (unit: %) in the column of "2C charge / discharge", and the numerical values (unit: %) in the column of "5C charge / discharge" respectively indicate the cooling improvement rates for 1C charge / discharge, 2C charge / discharge, and 5C charge / discharge.

[0077]

[0078] The cooling improvement rate (unit: %) is defined by the heat balance H (unit: W) and the reference heat balance H Ｒ (unit: W) as shown in the following formula (1). Cooling improvement rate = (1 - H / H Ｒ ) × 100 (1) The heat balance H is calculated from the heat generation amount H １ (unit: W) of the battery cell and the heat absorption amount H ２ (unit: W) of the cooling plate as shown in the following formula (2). H = H １ - H ２ (2) The heat generation amount H １ is calculated from the current I (unit: A) flowing through the battery cell and the internal resistance R (unit: Ω) of the battery cell as shown in the following formula (3). H １ = I ２ R (3) The heat absorption amount H ２ is calculated from the temperature difference ΔT (unit: K) between the temperature of the battery cell and the temperature of the cooling water of the cooling plate and the thermal resistance R ｔｈ (unit: K / W) between the battery element and the cooling plate as shown in the following formula (4). H ２ = ΔT / R ｔｈ (4) The reference heat balance H Ｒ is the heat balance of the battery cell according to the reference example. In the calculation of the reference heat balance H Ｒ , ΔT was taken as the temperature difference (unit: K) between the temperature of the battery cell and the temperature of the air around the battery cell.

[0079] From the comparison between Example 1 and Comparative Example 1, it can be said that in a battery cell having an exterior material that wraps the battery element, the cooling improvement rate can be improved by providing an internal thermal conductive adhesive.

[0080] A comparison of Example 2 and Comparative Example 2 suggests that in a battery cell having an outer covering material wrapped around the battery element, the cooling efficiency can be improved by providing an internal thermally conductive adhesive.

[0081] This application claims priority based on Japanese Patent Application No. 2024-192776, filed on November 1, 2024, and incorporates all of its disclosures herein.

[0082] 10A Battery module, 100A, 100B Battery cell, 110A, 110B Battery element, 111B Laminate, 112B Positive electrode, 113B Lead-out positive electrode current collector, 114B Negative electrode, 115B Lead-out negative electrode current collector, 116B Separator, 117B Folded section, 118B Enclosure section, 120A Outer material, 120B Terminals, 122A First laminate film, 124A Second laminate film, 130B Cover material, 132A Positive electrode terminal, 134A Negative electrode terminal, 136A Terminal group, 140B Outer material, 142B Wrapping section, 144B Lead-out section, 145B First lead-out section, 146B Second lead-out section, 150A, 150B Internal thermal conductive adhesive, internal adhesive, 200 Compression pad, 300 First voltage detection device, 310 First protector, 312 First opening, 320 First voltage detection terminal, 330 First voltage detection line, 340 First connector, 350 First busbar, 400 Second voltage detection device, 410 Second protector, 412 Second opening, 420 Second voltage detection terminal, 430 Second voltage detection line, 440 Second connector, 450 Second busbar, 500 Housing, 510 First plate, 520 Second plate, 530 Third plate, 540 Fourth plate, 550 Fifth plate, 560 Sixth plate, 610 Structural adhesive, 620 External thermal conductive adhesive, external adhesive

Claims

1. A battery cell comprising: a battery element; an outer casing material that seals the battery element; and a heat conduction element at least partially located between the battery element and the outer casing material.

2. The battery cell according to claim 1, wherein the heat conduction element is bonded to the battery element and the exterior material.

3. A battery module comprising: a battery cell according to claim 1 or 2; a heat exchange element; wherein the heat conduction element is at least partially located between the battery element and a portion of the exterior material located between the heat conduction element and the heat exchange element.

4. The battery module according to claim 3, further comprising other heat-conducting elements located at least partially between the portion of the exterior material and the heat exchange element.

Images