Battery module

Abstract

The present invention provides a battery module that can achieve high uniformity of surface pressure on elastic members. [Solution] The battery module comprises a battery cell stack in which a plurality of battery cells 11 are stacked, and an elastic member 14A disposed between the plurality of battery cells 11. The elastic member 14A comprises stacked pouches 20A and 20B. Pouch 20A (or 20B) has a third sealing portion 21C extending in a direction perpendicular to the stacking direction of the battery cells 11, and is filled with gas. The third sealing portion 21C faces the adjacent pouch 20B (or 20A).

Description

[Technical Field]

[0001] This invention relates to a battery module. [Background technology]

[0002] In recent years, research and development has been conducted on battery modules that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Patent Document 1 describes a module containing a flat-type secondary battery. In this module, a module casing that pressurizes and fixes the flat-type secondary battery is placed between the module casing and the flat-type secondary battery, with a fluid-containing bag that seals and encloses a fluid in between. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-303579 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, when the fluid-containing bag described in Patent Document 1 is placed between multiple battery cells, air can enter between the fluid-containing bag and the battery cells, which tends to reduce the uniformity of the surface pressure.

[0006] The present invention aims to provide a battery module that can achieve high uniformity of surface pressure of elastic members. [Means for solving the problem]

[0007] (1) A battery module comprising a battery cell stack in which a number of battery cells are stacked, and an elastic member disposed between the number of battery cells, wherein the elastic member comprises two stacked pouches, each pouch having a sealing portion extending in a direction perpendicular to the stacking direction of the battery cells, and filled with gas, the sealing portions facing adjacent pouches.

[0008] (2) The battery module according to (1), wherein the elastic member is formed by stacking the two pouches so that the sealing portion does not interfere with each other.

[0009] (3) The battery module according to (1) or (2), further comprising a plate-shaped member disposed between the two pouches.

[0010] (4) The battery module according to (3), wherein the plate-shaped member has a thermal conductivity of 1 W / (m·K) or more.

[0011] (5) The battery module according to (1) or (2), further comprising a corrugated leaf spring positioned between the two pouches.

[0012] (6) The pouch is a battery module according to any one of items (1) to (5), wherein the internal pressure is 0.1 MPa or more and 3.0 MPa or less.

[0013] (7) The battery module according to any one of (1) to (6), wherein the elastic member further comprises elastic foam disposed on both sides of the stacking direction of the battery cells of the two stacked pouches.

[0014] (8) The battery module according to any one of (1) to (7), wherein the battery cell includes a cell having a negative electrode composite layer containing lithium metal or lithium alloy.

[0015] (9) The battery module according to any one of (1) to (8), wherein the battery cell includes a solid battery cell.

Effects of the Invention

[0016] According to the present invention, a battery module capable of increasing the uniformity of surface pressure of an elastic member can be provided.

Brief Description of the Drawings

[0017] [Figure 1] It is a side view showing a battery module according to an embodiment of the present invention. [Figure 2A] It is a partially enlarged perspective view of the battery module of Figure 1. [Figure 2B] It is a schematic diagram showing a cross section taken along line A-A of Figure 2A. [Figure 2C] It is a schematic diagram showing a cross section taken along line B-B of Figure 2A. [Figure 3A] It is a schematic diagram showing a cross section of a modified example of the battery module of Figure 2B. [Figure 3B] It is a schematic diagram showing a cross section of a modified example of the battery module of Figure 2C. [Figure 4] It is a schematic diagram showing a cross section of a modified example of the battery module of Figure 2B.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0019] [Battery Module] Figure 1 shows a battery module according to an embodiment of the present invention.

[0020] The battery module 10 comprises battery cell stacks 11A and 11B in which a plurality of battery cells 11 are stacked, end plates 12A and 12B provided at both ends of the battery cell stacks 11A and 11B in the stacking direction, and a center plate 12C provided between the battery cell stacks 11A and 11B. The battery module 10 also includes bind bars 13A and 13B between the end plates 12A and 12B to restrain the battery cell stacks 11A and 11B. The restraining pressure by the bind bars 13A and 13B is not particularly limited, but is, for example, 1.0 MPa or more and 2.5 MPa or less.

[0021] The battery module 10 has elastic members 14A positioned between multiple battery cells 11, and elastic members 14B positioned between the battery cell stack 11A and the end plate 12A and center plate 12C, and between the battery cells 11 and the end plate 12B and center plate 12C. In this case, since the elastic member 14B is in contact with one battery cell 11, it is not particularly limited as long as it has at least half the elasticity of the elastic member 14A that is in contact with two battery cells 11. From the viewpoint of the energy density of the battery module 10, it is preferable that the elastic member 14B has the same configuration as the elastic member 14A except that its thickness is about half, but it may also be identical to the elastic member 14A.

[0022] As shown in Figures 2A, 2B, and 2C, the elastic member 14A comprises stacked pouches 20A and 20B. Pouch 20A (or 20B) has a third sealing portion 21C that extends in the longitudinal direction (AA direction) perpendicular to the stacking direction of the battery cell 11, and is filled with gas. At this time, the third extending portion 21C faces the adjacent pouch 20B (or 20A). Therefore, even if air enters between pouch 20A (or 20B) and the elastic foam 23A (or 23B) described later, the uniformity of the surface pressure of the elastic member 14A is increased. This is also true when the elastic foams 23A and 23B are omitted. Note that in Figure 2A, the battery cell 11 and the elastic foams 23A and 23B are omitted.

[0023] The elastic member 14A is constructed by laminating pouches 20A and 20B so that the third sealing portion 21C does not interfere with it. This results in increased uniformity of the surface pressure of the elastic member 14A.

[0024] The internal pressure of pouches 20A and 20B is preferably between 0.1 MPa and 3.0 MPa, and more preferably between 1.0 MPa and 2.5 MPa. When the internal pressure of pouches 20A and 20B is 0.1 MPa or higher, the uniformity of the surface pressure of the elastic member 14A is increased, and when it is 3.0 MPa or lower, damage to pouches 20A and 20B is suppressed even if the battery cells 11 expand and contract due to charging and discharging of the battery cells 11.

[0025] As shown in Figure 2B, pouch 20A (or 20B) has a first sealing portion 21A and a second sealing portion 21B at both ends in the longitudinal direction (AA direction) perpendicular to the stacking direction of the battery cells 11.

[0026] In this configuration, the elastic member 14A further comprises a first support member 22A that supports substantially the entire area of ​​the first sealing portion 21A, and a second support member 22B that supports substantially the entire area of ​​the second sealing portion 21B. Furthermore, the first support member 22A and the second support member 22B are positioned, for example, by a positioning member installed on the battery module 10.

[0027] As shown in Figure 2B, the elastic member 14A further comprises elastic foams 23A and 23B positioned on both sides of the stacking direction of the battery cells 11 in the stacked pouches 20A and 20B. In this case, when the elastic member 14A is compressed due to the expansion of the battery cells 11 during charging, the elastic foams 23A and 23B are interposed between the battery cells 11 and the pouches 20A and 20B, thereby increasing the uniformity of the surface pressure of the elastic member 14A.

[0028] The elastic member 14A may further include a plate-shaped member 40 positioned between pouches 20A and 20B, as shown in Figures 3A and 3B. This suppresses misalignment of the battery cells 11 in the stacking direction of pouches 20A and 20B. The material constituting the plate-shaped member 40 is not particularly limited, but examples include resin and metal.

[0029] The thermal conductivity of the plate-shaped member 40 is preferably 1 W / (m·K) or higher, and more preferably 3 W / (m·K) or higher. When the thermal conductivity of the plate-shaped member 40 is 1 W / (m·K) or higher, the temperature rise of the battery cell 11 is suppressed. The thermal conductivity of the plate-shaped member 40 is, for example, 236 W / (m·K) or lower. The material having a thermal conductivity of 1 W / (m·K) or higher is not particularly limited, but examples include high thermal conductivity polycarbonate resin, carbon fiber reinforced plastic (CFRP), stainless steel (SUS), and metals such as aluminum alloys.

[0030] Furthermore, the elastic member 14A may further include a corrugated leaf spring 50 positioned between the pouches 20A and 20B, as shown in Figure 4. This suppresses the reduction in the elasticity of the elastic member 14A even if the pouches 20A or 20B are damaged. The corrugated leaf spring 50 preferably contains fiber-reinforced plastic (FRP). This ensures that the corrugated leaf spring 50 has both heat resistance and heat insulation properties. Examples of FRP include carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP).

[0031] There are no particular limitations on the method for fixing the corrugated leaf spring 50 to the pouch 20A (or 20B), but one example is to bond the corrugated leaf spring 50 to the pouch 20A (or 20B) with an elastic adhesive. The corrugated leaf spring 50 is manufactured, for example, by a press molding method.

[0032] The pouch 20A (or 20B) is not particularly limited as long as it is elastic and can follow the expansion and contraction of the battery cell 11 during charging and discharging, and can be sealed, for example, an aluminum film is sandwiched between stretchable resin films. The stretchable resin is not particularly limited, but examples include polypropylene, polyamide, and polyester.

[0033] The method for forming the first sealing portion 21A, the second sealing portion 21B, and the third sealing portion 21C is not particularly limited, but one method is to heat-seal the stretchable resin constituting the pouch 20A (or 20B).

[0034] Pouch 20A (or 20B) is not particularly limited, but examples include pillow pouches (commercially available). The gas sealed in pouch 20A (or 20B) is not particularly limited, but examples include air.

[0035] The materials constituting the first support member 22A and the second support member 22B are not particularly limited, but include resin and metal.

[0036] The Poisson's ratio of the elastic foams 23A and 23B is preferably 0.3 or less. When the Poisson's ratio of the elastic foams 23A and 23B is 0.3 or less, the elastic foams 23A and 23B can more easily absorb the change in thickness due to the expansion and contraction of the battery cell 11. For example, the Poisson's ratio of the elastic foams 23A and 23B is 0.01 or more.

[0037] The thickness of the elastic foams 23A and 23B when the battery cell is charged to 100% is not particularly limited, but is, for example, 0.05 mm or more and 0.1 mm or less.

[0038] The porosity of the elastic foams 23A and 23B is not particularly limited, but is, for example, 30% to 95%. The materials constituting the elastic foams 23A and 23B are not particularly limited, but include, for example, polyurethane, silicone resin, ethylene propylene rubber, styrene resin, olefin resin, polyamide, and polyester.

[0039] The method for fixing the elastic foam 23A (or 23B) to the pouch 20A (or 20B) is not particularly limited, but one example is to adhere the elastic foam 23A (or 23B) to the pouch 20A (or 20B) with an elastic adhesive.

[0040] [cell] The cells constituting the battery cell 11 are not particularly limited, but examples include solid battery cells such as all-solid-state battery cells and semi-solid-state battery cells, and non-aqueous electrolyte battery cells having a negative electrode composite layer containing lithium metal or lithium alloy. The elements other than lithium that constitute the lithium alloy are not particularly limited, but examples include Sn, Ag, Mg, In, Si, and Al. Among these, solid battery cells having a negative electrode composite layer containing lithium metal or lithium alloy are preferred from the viewpoint of energy density.

[0041] The following describes an example of an all-solid-state battery cell.

[0042] An all-solid-state battery cell comprises a negative electrode current collector, a negative electrode composite layer containing lithium metal or a lithium alloy, a solid electrolyte layer, a positive electrode composite layer, and a positive electrode current collector.

[0043] The material constituting the negative electrode current collector is not particularly limited, and examples thereof include silver, palladium, gold, platinum, aluminum, copper, nickel, and stainless steel, as well as carbon. Among these, copper, stainless steel, and nickel are preferred from the viewpoints of electrical conductivity and cost.

[0044] The shape of the negative electrode current collector is not particularly limited, and examples thereof include a foil shape, a plate shape, a mesh shape, a non-woven fabric shape, and a foam shape.

[0045] The solid electrolyte constituting the solid electrolyte layer is not particularly limited, and examples thereof include a sulfide solid electrolyte and an oxide solid electrolyte.

[0046] The form of the solid electrolyte is not particularly limited, and examples thereof include particles.

[0047] The content of the solid electrolyte in the solid electrolyte layer is not particularly limited, and is, for example, 50 mass% or more and 99 mass% or less.

[0048] The solid electrolyte layer may further contain a binder or the like.

[0049] The method for forming the solid electrolyte layer is not particularly limited, and examples thereof include a method of applying a slurry containing a solid electrolyte and a solvent.

[0050] The positive electrode mixture layer contains a positive electrode active material. The positive electrode active material is not particularly limited, and examples thereof include lithium cobaltate (LiCoO₂), lithium nickelate (LiNiO₂), LiNi p Mn q Co r O₂(p+q+r=1), LiNi p Al q Co r O₂(p+q+r=1), lithium manganate (LiMn₂O₄), Li 1+x Mn 2-x-y M yExamples include O4(x+y=2) (where M is one or more elements selected from the group consisting of Al, Mg, Co, Fe, Ni, and Zn), lithium titanate, and LiMPO4 (where M is one or more elements selected from the group consisting of Fe, Mn, Co, and Ni).

[0051] The content of the positive electrode active material in the positive electrode composite layer is not particularly limited, but for example, it is 50% by mass or more and 99% by mass or less.

[0052] The positive electrode composite layer may further contain a solid electrolyte. The solid electrolyte is not particularly limited as long as it is capable of conducting lithium ions, but examples include oxide solid electrolytes and sulfide solid electrolytes.

[0053] The positive electrode composite layer may further contain a binder, a conductive additive, and the like.

[0054] The method for forming the positive electrode composite layer is not particularly limited, but one example is a method of applying a slurry containing a positive electrode active material and a solvent.

[0055] The materials used to constitute the positive electrode current collector are not particularly limited, but examples include aluminum, aluminum alloys, stainless steel, nickel, iron, and titanium. Among these, aluminum, aluminum alloys, and stainless steel are preferred.

[0056] The shape of the positive electrode current collector is not particularly limited, but examples include foil-shaped and plate-shaped.

[0057] Although embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and the above embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Explanation of Symbols]

[0058] 10 Battery Modules 11 battery cells 11A, 11B battery cell stack 12A, 12B end plates 12C Center Plate 13A, 13B Bind Bar 14A, 14B Elastic members 20A, 20B pouches 21A 1st sealing part 21B 2nd sealing part 21C 3rd sealing part 22A First support member 22B Second support member 23A, 23B Elastic foam 40 Plate-shaped member 50 Corrugated leaf spring

Claims

1. A battery cell stack in which multiple battery cells are stacked, The battery comprises an elastic member disposed between the plurality of battery cells, The elastic member comprises two stacked pouches, The pouch has a sealing portion that extends in a direction perpendicular to the stacking direction of the battery cells, and is filled with gas. The sealing portion is a battery module facing the adjacent pouch.

2. The battery module according to claim 1, wherein the elastic member is formed by stacking the two pouches so that the sealing portion does not interfere with each other.

3. The battery module according to claim 1 or 2, further comprising a plate-shaped member disposed between the two pouches.

4. The battery module according to claim 3, wherein the plate-shaped member has a thermal conductivity of 1 W / (m·K) or more.

5. The battery module according to claim 1 or 2, further comprising a corrugated leaf spring positioned between the two pouches.

6. The battery module according to claim 1 or 2, wherein the pouch has an internal pressure of 0.1 MPa or more and 3.0 MPa or less.

7. The battery module according to claim 1 or 2, wherein the elastic member further comprises elastic foam disposed on both sides of the stacking direction of the battery cells of the two stacked pouches.

8. The battery module according to claim 1 or 2, wherein the battery cell includes a cell comprising a negative electrode composite layer containing lithium metal or a lithium alloy.

9. The battery module according to claim 1 or 2, wherein the battery cell includes a solid battery cell.

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