Battery

Abstract

A battery is provided with: a rectangular single cell stack in which a plurality of rectangular single cells, each of which has terminals on both end surfaces in the longitudinal direction, are stacked; and a case that houses the cell stack. The unit cell stack includes metallic binding members that bind both lower ends of the plurality of rectangular unit cells in the longitudinal direction, and the binding members are fixed to the case with a thermally conductive adhesive.

Description

Technical Field

[0001] The present disclosure relates to batteries. Background Art

[0002] In conventional batteries, terminals are provided on the top surfaces of stacked rectangular cells. In recent years, batteries have also been developed in which terminals are provided on the longitudinal end surfaces of stacked rectangular cells, as disclosed in Patent Document 1.

[0003] Patent Document 1: U.S. Patent Application Publication No. 2022 / 0302533 Summary of the Invention

[0004] When charging a battery, the temperature near the terminals of each prismatic cell rises. This creates a problem of localized temperature rise within the prismatic cell. This problem becomes particularly pronounced during rapid charging.

[0005] The present disclosure has been made in view of such circumstances, and provides a battery capable of suppressing a local temperature rise inside a prismatic cell during charging.

[0006] A battery according to one embodiment of the present disclosure includes: A rectangular parallelepiped cell stack consisting of a plurality of stacked square cells with terminals provided on both end faces in the longitudinal direction; and a housing for housing the battery stack; in, The cell stack includes metal restraining members for restraining both lower end portions in the longitudinal direction of the plurality of rectangular cells. The restraining member is fixed to the housing by a thermally conductive adhesive.

[0007] In the battery disclosed herein, the lower longitudinal ends of the cell stack are restrained by metal restraining members, which are fixed to the housing with a thermally conductive adhesive. This allows heat generated near the terminals during charging to be dissipated to the housing via the restraining members and the thermally conductive adhesive. Consequently, localized temperature increases within the prismatic cells during charging can be suppressed.

[0008] Alternatively, an insulating plate may be provided between the plurality of prismatic cells and the restraining member, and through-holes provided in the insulating plate corresponding to the plurality of prismatic cells may be filled with an insulating, thermally conductive material. This configuration improves thermal conductivity between the prismatic cells and the restraining member while ensuring insulation between the prismatic cells and the restraining member.

[0009] The thermally conductive material may be the same material as the thermally conductive adhesive. With such a structure, the battery can be easily manufactured.

[0010] A cooler may be further provided on the lower side of the bottom plate of the housing. With this configuration, heat generated in the cell stack during charging can be more effectively dissipated from the bottom plate of the housing via the restraining members and the thermally conductive adhesive.

[0011] The restraining member may be a metal belt having an L-shaped cross section.

[0012] According to the present disclosure, it is possible to provide a battery capable of suppressing a local temperature rise inside a prismatic cell during charging. The above and other objects, features and advantages of the present disclosure will be more fully understood from the detailed description and accompanying drawings given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a perspective view showing a cell stack in the battery according to the first embodiment. Figure 2 This is a perspective view showing a cell stack in the battery according to the first embodiment. Figure 3 This is a cross-sectional view showing the battery according to the first embodiment. Figure 4 It is a perspective view showing the arrangement of the insulating plate IP1 with respect to the rectangular cells C1 to C6 . Figure 5 It is a perspective view showing the arrangement of the insulating plate IP2 with respect to the rectangular cells C1 to C6 . DETAILED DESCRIPTION

[0014] Hereinafter, the specific embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of description.

[0015] (First embodiment) First, refer to Figures 1 to 3 , the structure of the battery involved in the first embodiment is described. Figure 1 and Figure 2 Each of them is a perspective view showing a cell stack in the battery according to the first embodiment. Figure 3 This is a cross-sectional view showing the battery according to the first embodiment.

[0016] The battery according to this embodiment is used, for example, as a vehicle-mounted battery. The vehicle equipped with the battery according to this embodiment is not particularly limited, but may be, for example, an electric vehicle, a hybrid vehicle, or a fuel cell vehicle that can be driven by power supplied from the battery. In addition, of course, Figures 1 to 3 The right-handed XYZ orthogonal coordinates shown in the other figures are for the purpose of explaining the positional relationship of the components. Figure 1 In the figures, the positive direction of the Z axis is usually the vertical upward direction, and the XY plane is the horizontal plane, which is common among the drawings.

[0017] like Figure 3 As shown in FIG. 1 , the battery according to the first embodiment includes a cell stack CS, an upper case UC, a lower case LC, and a cooler CO. Here, the cell stack CS is as shown in FIG. Figure 1 and Figure 2 As shown, it has square cells C1 to C6, bus bars B1 to B5, and metal strips MB1 and MB2, and as shown Figure 3 As shown, adhesive layers AL1 and AL2, insulating plates IP1 and IP2, and heat conducting layers TL1 and TL2 are provided. In addition, Figure 3 In FIG, the square single cell C1 and the cooler CO are shown by a side view rather than a cross-sectional view.

[0018] First, refer to Figures 1 to 3 , the structure of the single cell stack CS is explained. like Figure 1 and Figure 2 As shown, the prismatic cells C1-C6 are rectangular parallelepiped cells extending in the Y-axis direction. The prismatic cells C1-C6 are stacked in the thickness direction (X-axis direction) to form a cell stack CS. The prismatic cells C1-C6 are secondary batteries such as lithium-ion batteries and nickel-metal hydride batteries.

[0019] In addition, Figure 1 and Figure 2 In FIG, the single cell stack CS is shown in a simplified manner. Figure 1 and Figure 2 The cell stack CS shown is composed of six prismatic cells C1 to C6, but is usually composed of more prismatic cells. The number of prismatic cells constituting the cell stack CS is not particularly limited; it can be a plurality.

[0020] Furthermore, a heat insulating plate (not shown) or a spacer for adjusting the distance may be inserted between adjacent rectangular single cells. Furthermore, end plates (not shown) may be provided at both ends of the cell stack CS in the stacking direction (X-axis direction).

[0021] like Figure 1 As shown in FIG. 1 , a positive terminal PT1 is provided on one end face (the end face on the negative side of the Y axis) in the longitudinal direction of the rectangular cell C1. Figure 1 The positive terminal PT1 shown is rectangular in shape when viewed from the XZ plane and is provided so as to protrude outward from the end surface of the square cell C1. Figure 1 The positive electrode terminal PT1 shown is provided on the upper side (Z-axis positive side) of the end surface of the rectangular cell C1. The positive electrode terminal PT1 is made of a metal material such as copper having excellent electrical conductivity.

[0022] Likewise, Figure 1 As shown, a negative terminal NT2 is provided at one end face in the longitudinal direction (end face on the negative side in the Y-axis) of the square cell C2 adjacent to the square cell C1. A positive terminal PT3 is provided at one end face in the longitudinal direction (end face on the negative side in the Y-axis) of the square cell C3 adjacent to the square cell C2. A negative terminal NT4 is provided at one end face in the longitudinal direction (end face on the negative side in the Y-axis) of the square cell C4 adjacent to the square cell C3. A positive terminal PT5 is provided at one end face in the longitudinal direction (end face on the negative side in the Y-axis) of the square cell C5 adjacent to the square cell C4. A negative terminal NT6 is provided at one end face in the longitudinal direction (end face on the negative side in the Y-axis) of the square cell C6 adjacent to the square cell C5.

[0023] like Figure 1 As shown, the negative terminal NT2 of the square cell C2, the positive terminal PT3 of the square cell C3, the negative terminal NT4 of the square cell C4, the positive terminal PT5 of the square cell C5, and the negative terminal NT6 of the square cell C6 have the same shape as the positive terminal PT1 of the square cell C1 and are configured in the same manner.

[0024] And, as Figure 1 As shown, the positive terminal PT1 of the adjacent prismatic cell C1 and the negative terminal NT2 of the prismatic cell C2 are electrically connected by a plate-shaped bus bar B1. Similarly, the positive terminal PT3 of the adjacent prismatic cell C3 and the negative terminal NT4 of the prismatic cell C4 are electrically connected by a plate-shaped bus bar B3. Similarly, the positive terminal PT5 of the adjacent prismatic cell C5 and the negative terminal NT6 of the prismatic cell C6 are electrically connected by a plate-shaped bus bar B5.

[0025] On the other hand, Figure 2 As shown in FIG. 1 , a negative terminal NT1 is provided on the other end face (the end face on the positive side of the Y axis) in the longitudinal direction of the rectangular cell C1. Figure 2 The negative terminal NT1 is shown with Figure 1The positive terminal PT1 shown is also rectangular in shape when viewed in the XZ plane and is provided so as to protrude outward from the end surface of the rectangular cell C1. Figure 2 The negative terminal NT1 is shown with Figure 1 The positive terminal PT1 is similarly provided on the upper side (Z-axis positive side) of the end face of the rectangular cell C1. The negative terminal NT1 is similarly formed of a metal material such as copper having excellent conductivity.

[0026] Likewise, Figure 2 As shown, a positive terminal PT2 is provided on the other end face in the longitudinal direction (the end face on the positive direction of the Y axis) of the square cell C2 adjacent to the square cell C1. A negative terminal NT3 is provided on the other end face in the longitudinal direction (the end face on the positive direction of the Y axis) of the square cell C3 adjacent to the square cell C2. A positive terminal PT4 is provided on the other end face in the longitudinal direction (the end face on the positive direction of the Y axis) of the square cell C4 adjacent to the square cell C3. A negative terminal NT5 is provided on the other end face in the longitudinal direction (the end face on the positive direction of the Y axis) of the square cell C5 adjacent to the square cell C4. A positive terminal PT6 is provided on the other end face in the longitudinal direction (the end face on the positive direction of the Y axis) of the square cell C6 adjacent to the square cell C5.

[0027] like Figure 2 As shown, the positive terminal PT2 of the square cell C2, the negative terminal NT3 of the square cell C3, the positive terminal PT4 of the square cell C4, the negative terminal NT5 of the square cell C5, and the positive terminal PT6 of the square cell C6 have the same shape as the negative terminal NT1 of the square cell C1 and are configured in the same manner.

[0028] And, as Figure 2 As shown, the positive terminal PT2 of the adjacent prismatic cell C2 and the negative terminal NT3 of the prismatic cell C3 are electrically connected by a plate-shaped bus bar B2. Similarly, the positive terminal PT4 of the adjacent prismatic cell C4 and the negative terminal NT5 of the prismatic cell C5 are electrically connected by a plate-shaped bus bar B4. Like this, in Figure 1 and Figure 2 In the illustrated cell stack CS, rectangular cells C1 to C6 are connected in series via bus bars B1 to B5 .

[0029] also, Figure 2 The negative terminal NT1 of the illustrated rectangular cell C1 is not particularly limited, but is connected to the positive terminal of another cell stack via a bus bar (not shown), for example. Figure 2The positive terminal PT6 of the illustrated rectangular cell C6 is not particularly limited, but is connected to the negative terminal of another cell stack via a bus bar (not shown), for example. With such a structure, for example, a plurality of cell stacks can be connected in series.

[0030] Figure 1 and Figure 2 The bus bars B1 to B5 shown have the same structure, so bus bar B1 will be described. like Figure 1 As shown, the bus bar B1 is a plate-shaped member that electrically connects the positive terminal PT1 of the adjacently arranged rectangular cell C1 and the negative terminal NT2 of the rectangular cell C2. The bus bar B1 is made of a metal material such as copper having excellent electrical conductivity.

[0031] like Figure 1 As shown, busbar B1 is a plate-shaped member having a rectangular shape when viewed in the XZ plane. Busbar B1 is provided to substantially entirely cover the positive terminal PT1 of prismatic cell C1 and the negative terminal NT2 of prismatic cell C2. Busbar B1 includes a pair of welded portions WP1 and WP2, which are welded to the positive terminal PT1 of the adjacent prismatic cell C1 and the negative terminal NT2 of the adjacent prismatic cell C2, respectively.

[0032] Although not specifically limited, Figure 1 The welded portions WP1 and WP2 shown are provided at both ends in the X-axis direction on the lower side (Z-axis negative direction side) of the bus bar B1. Figure 1 Welded portions WP1 and WP2 before welding are shown. Figure 1 The welded portions WP1 and WP2 shown are countersunk and have a thinner plate thickness than other areas. Figure 1 The welded portions WP1 and WP2 shown have a circular shape when viewed in the XZ plane, and have a through hole in the center.

[0033] While the welding method is not particularly limited, for example, by irradiating the weld portion WP1 with a laser beam from the negative side in the Y-axis direction, the bus bar B1 is welded to the positive terminal PT1 of the prismatic cell C1 at the weld portion WP1. Similarly, by irradiating the weld portion WP2 with a laser beam from the negative side in the Y-axis direction, the bus bar B1 is welded to the negative terminal NT2 of the prismatic cell C2 at the weld portion WP2.

[0034] like Figure 1 and Figure 2 As shown, metal bands (constraint members) MB1 and MB2 are L-shaped metal members with a YZ cross-section, extending along the entire length of the cell stack CS in the stacking direction. These metal bands MB1 and MB2 respectively constrain the longitudinal lower ends of the prismatic cells C1 to C6 (i.e., the cell stack CS). Furthermore, the metal strips MB1 and MB2 may be divided into a plurality of strips along the entire length of the cell stack CS.

[0035] In more detail, if Figure 3 As shown, metal strip MB1 is provided along the lower corners of the prismatic cells C1-C6 on the negative Y-axis side, forming an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of the prismatic cells C1-C6 and side plates that support the end surfaces of the prismatic cells C1-C6. Similarly, metal strip MB2 is provided along the lower corners of the prismatic cells C1-C6 on the positive Y-axis side, forming an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of the prismatic cells C1-C6 and side plates that support the end surfaces of the prismatic cells C1-C6. The metal strips MB1 and MB2 do not need to be L-shaped in YZ cross section, but may be, for example, flat plate-shaped.

[0036] like Figure 3 As shown, adhesive layer AL1 is made of a thermally conductive adhesive and fixes metal strip MB1 to the bottom plate of lower case LC. Similarly, adhesive layer AL2 is made of a thermally conductive adhesive and fixes metal strip MB2 to the bottom plate of lower case LC. The thermally conductive adhesive constituting the adhesive layers AL1 and AL2 has a thermal conductivity of, for example, 1 W / m·K or higher. The thermally conductive adhesive may also have insulating properties. Furthermore, the metal bands MB1 and MB2 may be fixed to the side plates of the housing, the bracket constituting the housing, or the like via the adhesive layers AL1 and AL2.

[0037] exist Figure 3 In the battery shown, heat generated near the positive terminal PT1 of the prismatic cell C1 during charging can be dissipated to the bottom plate of the lower case LC via the metal band MB1 and adhesive layer AL1. Similarly, heat generated near the negative terminal NT1 of the prismatic cell C1 during charging can be dissipated to the bottom plate of the lower case LC via the metal band MB2 and adhesive layer AL2. In other words, by connecting the metal bands MB1 and MB2 to the lower case LC via adhesive layers AL1 and AL2, localized temperature increases within the prismatic cell C1 during charging can be suppressed.

[0038] Here, in addition to Figure 3 In addition, refer to Figure 4 and Figure 5 , the insulating plates IP1 and IP2 are explained. Figure 4 It is a perspective view showing the arrangement of the insulating plate IP1 with respect to the rectangular cells C1 to C6 . Figure 5 It is a perspective view showing the arrangement of the insulating plate IP2 with respect to the rectangular cells C1 to C6 . like Figure 4 and Figure 5As shown, the insulating plates IP1 and IP2 are insulating members having an L-shaped YZ cross section and extending in the stacking direction over the entire length of the cell stack CS. The insulating plates IP1 and IP2 are made of resin, for example.

[0039] Here, if Figure 4 As shown in FIG. 1 , six through holes TH1 are provided on the insulating plate IP1 so as to correspond to the rectangular cells C1 to C6 respectively. Figure 5 As shown, six through holes TH2 are provided in the insulating plate IP2 so as to correspond to the rectangular cells C1 to C6 , respectively. Figure 4 and Figure 5 The through holes TH1 and TH2 shown are rectangular in shape when viewed in the XZ plane, but may be circular or elliptical, for example, and are not limited in any way.

[0040] On the other hand, Figure 3 As shown, insulating plate IP1 is positioned between the prismatic cells C1-C6 and metal band MB1 at the lower corners of the prismatic cells C1-C6 on the negative Y-axis side, electrically insulating them from each other. Similarly, insulating plate IP2 is positioned between the prismatic cells C1-C6 and metal band MB2 at the lower corners of the prismatic cells C1-C6 on the positive Y-axis side, electrically insulating them from each other.

[0041] In addition, although not particularly limited, Figure 3 The insulating plates IP1 and IP2 shown have an L-shaped YZ cross section corresponding to the metal bands MB1 and MB2 , are slightly larger than the metal bands MB1 and MB2 , and are provided so as to protrude from the metal bands MB1 and MB2 .

[0042] The heat conducting layer TL1 is made of a heat conducting material having insulating properties, such as Figure 3 As shown, the through holes TH1 provided in the insulating plate IP1 are filled with the heat conductive layer TL1. That is, the heat conductive layer TL1 connects the metal ribbon MB1 and the rectangular cells C1 to C6 in a heat conductive manner while electrically insulating them. Similarly, the heat conductive layer TL2 is made of an insulating thermally conductive material and fills each through-hole TH2 provided in the insulating plate IP2. In other words, the heat conductive layer TL2 connects the metal ribbon MB2 and the prismatic cells C1 to C6 while electrically insulating and thermally conductively connecting them.

[0043] According to this structure, Figure 3In the battery shown, heat generated near the positive terminal PT1 of the prismatic cell C1 during charging can be dissipated to the bottom plate of the lower case LC via the thermally conductive layer TL1, metal tape MB1, and adhesive layer AL1. Similarly, heat generated near the negative terminal NT1 of the prismatic cell C1 during charging can be dissipated to the bottom plate of the lower case LC via the thermally conductive layer TL2, metal tape MB2, and adhesive layer AL2.

[0044] That is, by connecting the metal bands MB1 and MB2 connected to the lower case LC via adhesive layers AL1 and AL2 to the rectangular cells C1 to C6 via heat conductive layers TL1 and TL2, a local temperature rise inside the rectangular cell C1 during charging can be further suppressed.

[0045] Furthermore, the thermally conductive material constituting the thermally conductive layers TL1 and TL2 may be the same material as the thermally conductive adhesive constituting the adhesive layers AL1 and AL2. With such a structure, the battery can be easily manufactured. Furthermore, as long as the rectangular cells C1 to C6 can be insulated from the metal strips MB1 and MB2, the insulating plates IP1 and IP2 are not essential. Consequently, the heat conducting layers TL1 and TL2 are also not essential.

[0046] like Figure 3 As shown, the upper case UC and lower case LC form the housing for the cell stack CS. The upper case UC is a metal plate that covers the top of the cell stack CS, while the lower case LC supports the bottom of the cell stack CS. The bottom of the cell stack CS (i.e., the prismatic cells C1-C6) is electrically insulated from the top of the lower case LC by, for example, an insulating, thermally conductive layer (not shown). Furthermore, a plurality of cell stacks CS may be arranged in the Y-axis direction inside the casing (upper casing UC and lower casing LC).

[0047] The cooler CO cools the cell stack CS, i.e., the square cells C1 to C6. Figure 3 As shown, the cooler CO is arranged in contact with the bottom surface of the lower case LC and extends along the entire length of the cell stack CS in the stacking direction (X-axis direction). Although not particularly limited, within the cooler CO, for example, multiple refrigerant tubes extending in the X-axis direction are arranged in parallel along the Y-axis direction. The refrigerant flowing within the refrigerant tubes is, for example, water.

[0048] The longitudinal center (Y-axis direction) of the prismatic cells C1 to C6 is cooled by the cooler CO via the lower case LC. Meanwhile, the longitudinal end portions of the prismatic cells C1 to C6 are cooled by the cooler CO via the heat transfer layer TL1, metal tape MB1, adhesive layer AL1, and lower case LC.

[0049] As described above, in the battery involved in this embodiment, the two lower ends of the single cell stack CS in the longitudinal direction are respectively bound by metal strips MB1 and MB2 with L-shaped cross-sections, and the metal strips MB1 and MB2 are fixed to the bottom plate of the lower shell LC through adhesive layers AL1 and AL2 composed of thermally conductive adhesive.

[0050] Therefore, heat generated near the positive terminals PT1-PT6 and negative terminals NT1-NT6 of the prismatic cells C1-C6 during charging can be dissipated to the bottom plate of the lower case LC via the metal bands MB1 and MB2 and the adhesive layers AL1 and AL2. As a result, localized temperature increases within the prismatic cells C1-C6 during charging can be suppressed.

[0051] From the disclosure described above, it is obvious that the embodiments of the present disclosure can be changed in many ways. Such changes should not be regarded as departing from the spirit and scope of the present disclosure, and all such modifications obvious to those skilled in the art are intended to be included within the scope of the claims.

Claims

1. A battery comprising: A rectangular parallelepiped cell stack consisting of a plurality of stacked square cells with terminals provided on both end faces in the longitudinal direction; and a housing for housing the battery stack; in, The cell stack includes metal restraining members for restraining both lower end portions in the longitudinal direction of the plurality of rectangular cells. The restraining member is fixed to the housing by a thermally conductive adhesive.

2. The battery according to claim 1, wherein An insulating plate is provided between the plurality of square cells and the restraining member. The through holes provided in the insulating plate so as to correspond to the plurality of rectangular single cells are filled with a thermally conductive material having insulating properties.

3. The battery according to claim 2, wherein The thermally conductive material is the same material as the thermally conductive adhesive.

4. The battery according to any one of claims 1 to 3, wherein A cooler is further provided on the lower side of the bottom plate of the housing.

5. The battery according to any one of claims 1 to 3, wherein The restraining member is a metal belt having an L-shaped cross section.

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