Battery

Abstract

To provide a battery which can inhibit local temperature rise in a square cell during charging.SOLUTION: A battery includes: a rectangular parallelepiped shape cell stack in which a plurality of prismatic cells provided at both end surfaces in a longitudinal direction with terminals are laminated; and a case which houses the cell stack. The cell stack includes metal restraint members which restrain lower ends in the longitudinal direction of the prismatic cells. The restraint members are fixed to the case by a heat conductive adhesive.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] In conventional batteries, terminals are provided on the top surface of each stacked prismatic cell. In recent years, as disclosed in Patent Document 1, batteries have been developed in which terminals are provided on the longitudinal end surfaces of each stacked prismatic cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2022 / 0302533 Summary of the Invention [Problem to be solved by the invention]

[0004] When a battery is charged, the temperature near the terminals of each prismatic cell rises. This causes a localized temperature rise inside the prismatic cell. This problem is particularly noticeable during rapid charging.

[0005] The present disclosure has been made in consideration of the above circumstances, and provides a battery that can suppress local temperature increases inside prismatic cells during charging. [Means for solving the problem]

[0006] A battery according to one aspect of the present disclosure includes: a rectangular parallelepiped cell stack in which a plurality of rectangular cells, each having terminals on both longitudinal end faces, are stacked; a case that houses the cell stack, the cell stack includes metal restraining members that restrain both lower ends of the plurality of rectangular cells in the longitudinal direction, The restraining member is fixed to the case by a thermally conductive adhesive.

[0007] In the battery according to the present disclosure, both longitudinal lower ends of the cell stack are restrained by metal restraint members, which are fixed to the case with thermally conductive adhesive. Therefore, heat generated near the terminals during charging can be dissipated to the case via the restraint members and the thermally conductive adhesive. As a result, local temperature increases inside the prismatic cells during charging can be suppressed.

[0008] 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 each of the plurality of prismatic cells may be filled with an insulating, thermally conductive material. With this configuration, it is possible to increase thermal conduction 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, which makes the battery easier to manufacture.

[0010] A cooler may be further provided below the bottom plate of the case. With this configuration, heat generated in the cell stack during charging can be more effectively dissipated from the bottom plate of the case via the restraint member and the thermally conductive adhesive.

[0011] The restraining member may be a metal band having an L-shaped cross section. [Effects of the Invention]

[0012] The present disclosure makes it possible to provide a battery that can suppress local temperature increases inside prismatic cells during charging. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing a cell stack in a battery according to a first embodiment. [Figure 2] 1 is a perspective view showing a cell stack in a battery according to a first embodiment. [Figure 3] 1 is a cross-sectional view showing a battery according to a first embodiment. [Figure 4] FIG. 10 is a perspective view showing the arrangement of insulating plates IP1 relative to prismatic cells C1 to C6. [Figure 5] FIG. 10 is a perspective view showing the arrangement of insulating plates IP2 relative to prismatic cells C1 to C6. DETAILED DESCRIPTION OF THE INVENTION

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

[0015] (First embodiment) First, the configuration of the battery according to the first embodiment will be described with reference to Figures 1 to 3. Figures 1 and 2 are both perspective views showing a cell stack in the battery according to the first embodiment. Figure 3 is a cross-sectional view showing the battery according to the first embodiment.

[0016] The battery according to the present embodiment is used, for example, as an in-vehicle battery. The vehicle on which the battery according to the present embodiment is mounted is not particularly limited, but may be, for example, an electric vehicle, a hybrid vehicle, a fuel cell vehicle, or the like that can be driven by power supplied from the battery. Naturally, the right-handed XYZ Cartesian coordinate system shown in Figures 1 to 3 and other figures is for the convenience of explaining the positional relationship of the components. In Figure 1 and other figures, the positive direction of the Z axis is normally vertically upward, and the XY plane is the horizontal plane, which is common to all figures.

[0017] As shown in Fig. 3, 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 includes prismatic cells C1 to C6, bus bars B1 to B5, and metal bands MB1 and MB2 as shown in Figs. 1 and 2, and also includes adhesive layers AL1 and AL2, insulating plates IP1 and IP2, and thermally conductive layers TL1 and TL2 as shown in Fig. 3. In FIG. 3, the prismatic cell C1 and the cooler CO are shown in a side view rather than a cross-sectional view.

[0018] First, the configuration of the cell stack CS will be described with reference to FIGS. 1 and 2, the prismatic cells C1 to C6 are rectangular parallelepiped cells extending in the Y-axis direction. The prismatic cells C1 to C6 are stacked in the thickness direction (X-axis direction) to form a cell stack CS. The prismatic cells C1 to C6 are secondary batteries such as lithium-ion batteries or nickel-metal hydride batteries.

[0019] Note that the cell stack CS is shown in a simplified form in Figures 1 and 2. The cell stack CS shown in Figures 1 and 2 is composed of six prismatic cells C1 to C6, but is usually composed of more prismatic cells. On the other hand, the number of prismatic cells that make up the cell stack CS is not particularly limited, as long as it is plural.

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

[0021] As shown in Fig. 1, a positive electrode terminal PT1 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of the prismatic cell C1. Although not particularly limited, the positive electrode terminal PT1 shown in Fig. 1 has a rectangular shape when viewed in the XZ plane and is provided so as to protrude outward from the end face of the prismatic cell C1. The positive electrode terminal PT1 shown in Fig. 1 is provided on the upper side (the positive Z-axis direction) of the end face of the prismatic cell C1. The positive electrode terminal PT1 is made of a metal material such as copper, which has excellent conductivity.

[0022] Similarly, as shown in FIG. 1, a negative electrode terminal NT2 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C2 adjacent to prismatic cell C1. A positive electrode terminal PT3 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C3 adjacent to prismatic cell C2. A negative electrode terminal NT4 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C4 adjacent to prismatic cell C3. A positive electrode terminal PT5 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C5 adjacent to prismatic cell C4. A negative electrode terminal NT6 is provided on one longitudinal end face (the end face on the negative Y-axis direction) of prismatic cell C6 adjacent to prismatic cell C5.

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

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

[0025] On the other hand, as shown in Fig. 2, a negative electrode terminal NT1 is provided on the other longitudinal end face (end face on the Y-axis positive side) of the prismatic cell C1. Although not particularly limited, the negative electrode terminal NT1 shown in Fig. 2 has a rectangular shape in the XZ plane, similar to the positive electrode terminal PT1 shown in Fig. 1, and is provided so as to protrude outward from the end face of the prismatic cell C1. Furthermore, similar to the positive electrode terminal PT1 shown in Fig. 1, the negative electrode terminal NT1 shown in Fig. 2 is provided on the upper side (Z-axis positive side) of the end face of the prismatic cell C1. Similar to the positive electrode terminal PT1, the negative electrode terminal NT1 is made of a metal material such as copper, which has excellent conductivity.

[0026] Similarly, as shown in FIG. 2, a positive electrode terminal PT2 is provided on the other longitudinal end surface (the end surface on the positive Y-axis direction) of prismatic cell C2 adjacent to prismatic cell C1. A negative electrode terminal NT3 is provided on the other longitudinal end surface (the end surface on the positive Y-axis direction) of prismatic cell C3 adjacent to prismatic cell C2. A positive electrode terminal PT4 is provided on the other longitudinal end surface (the end surface on the positive Y-axis direction) of prismatic cell C4 adjacent to prismatic cell C3. A negative electrode terminal NT5 is provided on the other longitudinal end surface (the end surface on the positive Y-axis direction) of prismatic cell C5 adjacent to prismatic cell C4. A positive electrode terminal PT6 is provided on the other longitudinal end surface (the end surface on the positive Y-axis direction) of prismatic cell C6 adjacent to prismatic cell C5.

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

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

[0029] The negative electrode terminal NT1 of the prismatic cell C1 shown in Fig. 2 is connected to the positive electrode terminal of another cell stack via, for example, a bus bar (not shown), although this is not a limitation. The positive electrode terminal PT6 of the prismatic cell C6 shown in Fig. 2 is connected to the negative electrode terminal of yet another cell stack via, for example, a bus bar (not shown). This configuration allows, for example, multiple cell stacks to be connected in series.

[0030] The bus bars B1 to B5 shown in FIGS. 1 and 2 have the same configuration, so only the bus bar B1 will be described. 1, the busbar B1 is a plate-shaped member that electrically connects the positive electrode terminal PT1 of the adjacent prismatic cell C1 with the negative electrode terminal NT2 of the adjacent prismatic cell C2. The busbar B1 is made of a metal material such as copper, which has excellent electrical conductivity.

[0031] 1, the busbar B1 is, for example, a plate-like member having a rectangular shape when viewed in the XZ plane. The busbar B1 is provided so as to cover substantially the entire positive electrode terminal PT1 of the prismatic cell C1 and the negative electrode terminal NT2 of the prismatic cell C2. The busbar B1 has a pair of welds WP1 and WP2 welded to the positive electrode terminal PT1 of the prismatic cell C1 and the negative electrode terminal NT2 of the prismatic cell C2, respectively, which are arranged adjacent to each other.

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

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

[0034] 1 and 2, metal bands (restraint members) MB1 and MB2 are metal members with an L-shaped YZ cross section that extend in the stacking direction over the entire length of the cell stack CS. The metal bands MB1 and MB2 restrain both lower longitudinal ends of the prismatic cells C1 to C6 (i.e., the cell stack CS). The metal bands MB1 and MB2 may be divided into a plurality of bands and provided over the entire length of the cell stack CS.

[0035] 3, metal band MB1 is provided along the lower corners of prismatic cells C1-C6 on the negative Y-axis side, and has an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of prismatic cells C1-C6 and a side plate that supports the end surfaces of prismatic cells C1-C6. Similarly, metal band MB2 is provided along the lower corners of prismatic cells C1-C6 on the positive Y-axis side, and has an L-shaped YZ cross section. It includes a bottom plate that supports the bottom surfaces of prismatic cells C1-C6 and a side plate that supports the end surfaces of prismatic cells C1-C6. The metal bands MB1 and MB2 do not have to be L-shaped in YZ cross section, and may be, for example, flat.

[0036] 3, adhesive layer AL1 is made of a thermally conductive adhesive and fixes metal band MB1 to the bottom plate of lower case LC. Similarly, adhesive layer AL2 is made of a thermally conductive adhesive and fixes metal band MB2 to the bottom plate of lower case LC. The thermally conductive adhesive constituting the adhesive layers AL1 and AL2 is an adhesive having a thermal conductivity of, for example, 1 W / m·K or more. The thermally conductive adhesive may have insulating properties. The metal bands MB1 and MB2 may be fixed to the side plates of the case or brackets that constitute the case via adhesive layers AL1 and AL2.

[0037] In the battery shown in Figure 3, 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 the adhesive layers AL1 and AL2, local temperature increases inside the prismatic cell C1 during charging can be suppressed.

[0038] Here, the insulating plates IP1 and IP2 will be described with reference to Fig. 4 and Fig. 5 in addition to Fig. 3. Fig. 4 is a perspective view showing the arrangement of the insulating plate IP1 relative to the prismatic cells C1 to C6. Fig. 5 is a perspective view showing the arrangement of the insulating plate IP2 relative to the prismatic cells C1 to C6. 4 and 5, the insulating plates IP1 and IP2 are insulating members with an L-shaped YZ cross section that extend in the stacking direction over the entire length of the cell stack CS. The insulating plates IP1 and IP2 are made of, for example, resin.

[0039] Here, as shown in Fig. 4, the insulating plate IP1 has six through holes TH1 formed therein so as to correspond to the prismatic cells C1 to C6, respectively. Similarly, as shown in Fig. 5, the insulating plate IP2 has six through holes TH2 formed therein so as to correspond to the prismatic cells C1 to C6, respectively. The through holes TH1 and TH2 shown in FIGS. 4 and 5 are rectangular when viewed in the XZ plane, but may be circular or elliptical, and are not limited thereto.

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

[0041] Furthermore, although not particularly limited, the insulating plates IP1 and IP2 shown in FIG. 3 have an L-shaped YZ cross section corresponding to the metal bands MB1 and MB2, and are slightly larger than the metal bands MB1 and MB2, and are arranged so as to protrude beyond the metal bands MB1 and MB2.

[0042] The thermally conductive layer TL1 is made of an insulating thermally conductive material, and is filled into each of the through holes TH1 provided in the insulating plate IP1, as shown in Fig. 3. That is, the thermally conductive layer TL1 connects the metal band MB1 and the prismatic cells C1 to C6 in a thermally conductive manner while electrically insulating them from each other. Similarly, the thermally conductive layer TL2 is made of an insulating thermally conductive material and fills each of the through holes TH2 provided in the insulating plate IP2. That is, the thermally conductive layer TL2 connects the metal band MB2 and the prismatic cells C1 to C6 to each other in a thermally conductive manner while electrically insulating them from each other.

[0043] 3, heat generated near the positive electrode 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, the metal band MB1, and the adhesive layer AL1. Similarly, heat generated near the negative electrode 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, the metal band MB2, and the adhesive layer AL2.

[0044] In other words, by connecting the metal bands MB1 and MB2, which are connected to the lower case LC by the adhesive layers AL1 and AL2, to the prismatic cells C1 to C6 by the thermal conduction layers TL1 and TL2, the local temperature rise inside the prismatic cell C1 during charging can be further suppressed.

[0045] The thermally conductive material that forms the thermally conductive layers TL1 and TL2 may be the same material as the thermally conductive adhesive that forms the adhesive layers AL1 and AL2. Such a configuration makes it easier to manufacture the battery. Furthermore, if the prismatic cells C1 to C6 and the metal bands MB1 and MB2 can be insulated from each other, the insulating plates IP1 and IP2 are not essential, and therefore the thermally conductive layers TL1 and TL2 are not essential either.

[0046] As shown in Fig. 3, an upper case UC and a lower case LC constitute a case that houses a cell stack CS. The upper case UC is a metal plate that covers the top surface of the cell stack CS, and the lower case LC is a metal plate that supports the bottom surface of the cell stack CS. The bottom surface of the cell stack CS (i.e., the prismatic cells C1 to C6) and the top surface of the lower case LC are electrically insulated by, for example, an insulating heat-conducting layer (not shown). Note that a plurality of cell stacks CS may be arranged side by side in the Y-axis direction inside the cases (upper case UC and lower case LC).

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

[0048] The central portions of the prismatic cells C1 to C6 in the longitudinal direction (Y-axis direction) are cooled by the cooler CO via the lower case LC. On the other hand, the ends of the prismatic cells C1 to C6 in the longitudinal direction are cooled by the cooler CO via the thermal conduction layer TL1, the metal band MB1, the adhesive layer AL1, and the lower case LC.

[0049] As described above, in the battery of this embodiment, each of the two lower longitudinal ends of the cell stack CS is restrained by metal bands MB1 and MB2 with an L-shaped cross section, and the metal bands MB1 and MB2 are fixed to the bottom plate of the lower case LC by adhesive layers AL1 and AL2 made of a thermally conductive adhesive.

[0050] Therefore, heat generated near the positive electrode terminals PT1-PT6 and negative electrode 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, MB2 and adhesive layers AL1, AL2, thereby suppressing local temperature increases inside the prismatic cells C1-C6 during charging.

[0051] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0052] AL1, AL2 adhesive layer B1~B5 bus bar C1~C6 Prismatic cells CO cooler CS Cell Stack IP1, IP2 insulating plate LC Lower Case MB1, MB2 metal band NT1~NT6 Negative terminal PT1~PT6 Positive terminal TH1, TH2 through hole TL1, TL2 thermal conduction layers UC Upper Case WP1, WP2 welds

Claims

1. a rectangular parallelepiped cell stack in which a plurality of rectangular cells, each having terminals on both longitudinal end faces, are stacked; a case that houses the cell stack, the cell stack includes metal restraining members that restrain both lower ends of the plurality of rectangular cells in the longitudinal direction, The restraint member is fixed to the case by a thermally conductive adhesive. Battery.

2. an insulating plate is provided between the plurality of rectangular cells and c; through holes formed in the insulating plate so as to correspond to the plurality of rectangular cells, respectively, and filled with an insulating thermally conductive material; 10. The battery of claim 1.

3. the thermally conductive material is the same material as the thermally conductive adhesive; 3. The battery of claim 2.

4. A cooler is further provided below the bottom plate of the case. The battery according to any one of claims 1 to 3.

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

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