Battery module

Abstract

A battery module according to one embodiment of the present disclosure is provided with a battery case and a plurality of laminate batteries that are contained within the battery case; each one of the plurality of laminate batteries comprises an electrode body, a container part in which the electrode body is contained, and a sealing part which seals the periphery of the container part; the container part comprises an exhaust part and a main body part; and the inside of the battery case, except for the front end of the exhaust part, is filled with a molding resin.

Description

[Technical Field]

[0001] The present disclosure relates to a battery module. [Background technology]

[0002] A battery module generally includes a plurality of secondary batteries and a battery case that houses the plurality of secondary batteries. In recent years, the use of laminated batteries as secondary batteries has been considered in order to reduce weight. Furthermore, because secondary batteries can generate gas in the event of an abnormality, battery modules are also required to have a gas exhaust function to prevent explosion. Patent Document 1 discloses a battery module in which a molded resin is filled inside a battery case that houses a laminated battery to form a resin fixing portion, and a resin defect portion is provided to serve as a gas exhaust path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-190734 Summary of the Invention

[0004] However, when multiple batteries are used in a battery module, even if one battery overheats and emits flammable, high-temperature gas, it is necessary to prevent the abnormal overheating from spreading to adjacent batteries. The battery module disclosed in Patent Document 1 raises concerns about heat conduction between adjacent batteries due to resin defects in the area in contact with the laminated battery. Thus, the technology disclosed in Patent Document 1 does not adequately address battery damage caused by the propagation of abnormal overheating, and there is still room for improvement.

[0005] An object of the present disclosure is to provide a battery module that suppresses the spread of battery damage due to the propagation of overheating in an abnormal battery and ensures an exhaust path from the laminate battery.

[0006] A battery module according to one aspect of the present disclosure comprises a battery case and a plurality of laminated batteries housed within the battery case, each of the plurality of laminated batteries having an electrode body, a housing section that houses the electrode body, and a sealing section that seals the periphery of the housing section, the housing section including an exhaust section and a main body section, and the battery case being filled with molded resin except for the tip of the exhaust section.

[0007] In the battery module according to one embodiment of the present disclosure, the main body may be embedded in the molding resin.

[0008] In the battery module according to one embodiment of the present disclosure, each of the plurality of laminate batteries may have a plurality of housing sections.

[0009] In the battery module according to one aspect of the present disclosure, the exhaust portion of the housing portion may be provided so as to protrude from one side of the electrode body of the main body portion in the axial direction of the electrode body.

[0010] In a battery module according to one embodiment of the present disclosure, an exhaust path for gas discharged from the electrode body when the sealed portion of the laminated battery on the extension line of the tip of the exhaust portion is opened may be formed between the inner surface of the battery case and the upper surface of the molded resin filled in the battery case.

[0011] According to the battery module of one aspect of the present disclosure, it is possible to suppress the spread of battery damage caused by the propagation of overheating in an abnormal battery, and to ensure an exhaust path from the laminate battery. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is an exploded perspective view of a battery module according to an embodiment. [Figure 2] FIG. 2 is a plan view of a portion of the inside of a battery case in a battery module as an example of an embodiment, viewed from above. [Figure 3] FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. It should be noted that, when multiple embodiments and variations are included below, it is anticipated from the outset that new embodiments will be constructed by appropriately combining their characteristic features. Furthermore, among the components described below, components that are not recited in the independent claims that represent the highest concepts are optional components and are not essential components.

[0014] The accompanying drawings include schematic diagrams, and the dimensional ratios of the depth, width, height, etc. of each component in different drawings do not necessarily match. Furthermore, when the word "substantially" is used in this specification, it is used in the same sense as the word "roughly," and the requirement of "substantially ~" is met if the components are substantially the same.

[0015] First, an overview of a battery module 1 will be described with reference to Fig. 1. Fig. 1 is an exploded perspective view of a battery module 1 according to an embodiment. The battery module 1 includes a battery case 14 and a plurality of laminate batteries 10 housed in the battery case 14 in an upright position.

[0016] In this embodiment, the two laminate batteries 10 stand upright with their main planes approximately perpendicular to the bottom surface of the battery case 14. A total of three partition walls 12 are provided between the two laminate batteries 10 and around the laminate batteries 10. The number of laminate batteries 10 housed in the battery module 1 is not particularly limited. The number of partition walls is also not particularly limited. Below, the X direction is the depth direction, the Y direction is the width direction, and the Z direction is the height direction, with the +Z direction being the upward direction and the -Z direction being the downward direction. The installation orientation of the battery module 1 during use is not particularly limited; for example, the battery module 1 may be used with the Z direction parallel to the ground.

[0017] The battery case 14 is composed of a case body 14a and a lid 16 that closes the opening of the case body 14a. It forms the housing of the battery module 1 and houses the laminate batteries 10 and the partition walls 12. The shape of the battery case 14 is not particularly limited as long as it can house the laminate batteries 10 and the partition walls 12. For example, the case body 14a is a rectangular parallelepiped with an opening on the top surface. The lid 16 is a rectangular parallelepiped with an opening on the bottom surface and fits into the case body 14a to close the top opening of the case body 14a. The battery case 14 is filled with a molded resin (not shown in FIG. 1). That is, the molded resin fills the gap between the laminate batteries 10 and the partition walls 12 housed inside the battery case 14. Generally, the battery case 14 is provided with external terminals electrically connected to the laminate batteries 10 housed inside the battery case 14; however, the external terminals are omitted from FIG. 1.

[0018] The laminated battery 10 is primarily used as a power source for motive power. For example, the laminated battery 10 is used as a power source for motor-driven electric devices such as electric vehicles, power tools, power-assisted bicycles, electric motorcycles, electric wheelchairs, electric tricycles, and electric carts. However, the uses of the laminated battery 10 are not limited, and it may also be used as a power source for a variety of indoor and outdoor electrical devices, such as vacuum cleaners, radios, lighting devices, digital cameras, and video cameras.

[0019] The laminated battery 10 has an electrode assembly, a housing section 22 that houses the electrode assembly, and a sealing section 23 that seals the periphery of the housing section 22. Each laminated battery 10 may have multiple housing sections. In this embodiment, the laminated battery 10 has a cylindrical electrode assembly in each of eight housing sections 22 arranged in the width direction. In addition to the electrode assembly, the housing section 22 also contains, for example, an electrolyte. The electrolyte is, for example, a non-aqueous electrolyte containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent.

[0020] The laminated battery 10 has an exterior body made of two laminated sheets. The laminated sheets can be sheets made by laminating a metal layer and a resin layer. The laminated sheet has, for example, two resin layers sandwiching a metal layer, one of which is made of a thermocompression-bondable resin. An example of the metal layer is an aluminum layer.

[0021] The laminated battery 10 has an external shape that is, for example, approximately rectangular in plan view. The laminated battery 10 has sealing sections 23 formed by joining laminate sheets together, which seal the storage sections 22 that house the electrode assembly and other components. In this embodiment, the sealing sections 23 are formed at the edges of the laminated battery 10 and between the storage sections 22. In other words, the sealing sections 23 seal the storage sections 22 while also connecting adjacent storage sections 22 to each other.

[0022] The accommodation section 22 is a portion surrounded by the sealing section 23, and is provided by forming a recess capable of accommodating the electrode body in at least one of the two laminate sheets. In this embodiment, the recess is formed in both of the two laminate sheets, and the accommodation section 22 bulges out on both sides in the depth direction.

[0023] The cylindrical electrode body has a wound structure in which strip-shaped electrodes (positive and negative electrodes) are wound with a separator interposed therebetween. The shape of the electrode body is not limited to a cylindrical shape. The number of electrode bodies included in the laminate battery 10 is also not particularly limited. The structure of the electrode body is not limited to a wound type, and may be, for example, a stacked type in which multiple positive electrodes and multiple negative electrodes are alternately stacked one by one.

[0024] At the top end of the laminated battery 10, first electrode leads 24 extend from positions corresponding to each electrode body. At the bottom end of the laminated battery 10, second electrode leads 26 extend from positions corresponding to each electrode body. That is, at both the top and bottom ends of the laminated battery 10, the same number of electrode leads extend as there are electrode bodies.

[0025] For example, one end of the first electrode lead 24 is connected to the positive electrode in the electrode assembly, and one end of the second electrode lead 26 is connected to the negative electrode in the electrode assembly. The first electrode lead 24 may be connected to the negative electrode, and the second electrode lead 26 may be connected to the positive electrode. Alternatively, both the first electrode lead 24 and the second electrode lead 26 may extend from either the upper end or the lower end of the laminate battery 10. Generally, current collecting members such as metal plates are connected to the first electrode lead 24 and the second electrode lead 26, respectively, and the current collecting members are further connected to external terminals provided on the battery case 14 or the lid 16. However, electrical connecting members such as the current collecting members and external terminals are omitted from FIG. 1 .

[0026] Taking safety into consideration, multiple laminate batteries 10 may be packed as closely as possible within the battery module 1. For example, adjacent laminate batteries 10 may be arranged so that the electrode body of one laminate battery 10 is located between the adjacent electrode bodies of the other laminate battery 10. In other words, adjacent laminate batteries 10 may be arranged with a shift in the width direction so that the thickness in the depth direction is thinner.

[0027] In this embodiment, the partition walls 12 are provided between two laminate batteries 10 and around the two laminate batteries 10, but the partition walls 12 may also be provided only between multiple laminate batteries 10. The partition walls 12 are in an upright position similar to the laminate batteries 10 and are, for example, taller than the laminate batteries 10. The partition walls 12 function to position the laminate batteries 10, for example, by holding the laminate batteries 10 until the molding resin solidifies. The partition walls 12 may be, for example, a corrugated plate with repeated projections and depressions that conform to the shape of the storage compartment 22 that bulges out from the laminate batteries 10, or a flat plate.

[0028] The material of the partition wall 12 is not particularly limited, but is preferably insulating. Examples of materials for the partition wall 12 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE), elastic materials such as polyurethane, and silica-based insulating materials. Since the exterior of the laminated battery 10 is insulating, the partition wall 12 may be made of a metal plate, such as aluminum or an aluminum alloy, which has better heat dissipation properties than the molded resin 20, to improve the heat dissipation of the laminated battery 10.

[0029] Next, the configuration inside the battery case 14 of the battery module 1 will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a plan view of a part of the inside of the battery case 14 of the battery module 1, which is an example of an embodiment, viewed from above. Fig. 3 is a cross-sectional view taken along line AA in Fig. 2.

[0030] As shown in FIG. 2, the battery case 14 is filled with molded resin 20. The molded resin 20 is poured into the battery case 14 by pouring it into the case body 14a with the top opening facing upward and the laminated battery 10 and partition wall 12 positioned upright in the case body 14a. Filling the battery case 14 with molded resin 20 protects surrounding batteries from overheating due to an abnormality in the laminated battery 10, preventing fires from spreading. Furthermore, the upper ends of the multiple laminated batteries 10 protrude from the upper surface of the molded resin 20. Having the upper ends of the laminated batteries 10 protrude from the upper surface of the molded resin 20 ensures an exhaust path in the event of an abnormality. Specifically, the pressure of the gas generated in the housing section 22 opens the gap between the two laminated sheets that form the sealing section 23 at the top of the laminated battery 10, creating an exhaust path.

[0031] Examples of the mold resin 20 include acrylonitrile butadiene styrene (ABS) resin, polyvinyl chloride (PVC) resin, polycarbonate (PC) resin, polypropylene (PP) resin, polyethylene (PE) resin, polyamide (PA) resin, and urethane-based resin.

[0032] As shown in FIG. 3, the housing 22 is enclosed and sealed by a sealing section 23. The housing 22 includes an exhaust section 22a and a main body section 22b. The exhaust section 22a protrudes upward from one side of the electrode assembly of the main body section 22b. If an abnormality occurs and the internal pressure of the housing 22 increases, the sealing section 23 of the laminated battery 10 on the extension line of the tip of the exhaust section 22a is opened, and gas is discharged into the atmosphere from the top end of the laminated battery 10. The location of the exhaust section 22a is not particularly limited, but as shown in FIG. 3, it may be located on part of the outer edge of the main body section 22b. The term "upper" used here refers to the upward direction when the molded resin is filled inside the battery case 14. In FIG. 3, this refers to the X direction, one side of the axial direction of the electrode assembly, and one side of the standing direction of the laminated battery 10. The term "upper surface", together with the term "upper surface" used in the claims, indicates the surface facing upward when the molding resin is filled inside the battery case 14.

[0033] The main body 22b is a portion that houses the electrode assembly and electrolyte. The main body 22b has a cylindrical outer shape and is generally rectangular in plan view as shown in Figure 3. A first electrode lead 24 extends from the upper end of the main body 22b, and a second electrode lead 26 extends from the lower end of the main body 22b. A current collecting member such as a metal plate is connected to each of the first electrode lead 24 and the second electrode lead 26, and the first electrode leads 24 and the second electrode leads 26 of multiple laminate batteries 10 are connected to each other, and the multiple laminate batteries 10 are connected in parallel.

[0034] In Figure 3, the dotted line M represents the upper surface of the molded resin 20. That is, the space between the dotted line and the bottom surface of the case body 14a is filled with the molded resin 20, and in this embodiment, the main body 22b is buried in the molded resin 20. This allows the main body 22b that houses the electrode assembly to be surrounded by the molded resin 20, making it possible to more significantly suppress battery damage caused by heat conduction from an abnormal battery to surrounding batteries. Note that the upper surface of the molded resin 20 may be lower than the upper end of the main body 22b.

[0035] The tip of exhaust portion 22a is located above upper surface M of molded resin 20. In other words, the battery case 14 is filled with molded resin 20 except for the tip of exhaust portion 22a. This allows the sealing portion 23 above exhaust portion 22a to be opened without the tip of exhaust portion 22a being affected by molded resin 20. After opening sealing portion 23, gas is discharged from the electrode body through exhaust portion 22a, passing through an exhaust path formed between the inner surface of battery case 14 and upper surface M of molded resin 20, and is discharged to the outside of battery case 14 through an exhaust hole provided in battery case 14.

[0036] 3, G1 represents the distance between the tip of exhaust portion 22a and upper surface M of molded resin 20. The range of G1 that can ensure an exhaust path from laminated battery 10 is not particularly limited because it varies depending on the internal pressure of storage portion 22 in an abnormality and the peel strength of the two laminate sheets at sealing portion 23, but is, for example, 1 mm to 10 mm, and preferably 2 mm to 8 mm.

[0037] 3, G2 represents the distance between the tip of exhaust section 22a and the upper end of laminated battery 10. The range of G2 that allows an exhaust path from laminated battery 10 to be secured is not particularly limited, as it varies depending on factors such as the internal pressure of storage section 22 in an abnormality and the peel strength of the two laminate sheets at sealing section 23, but is, for example, 1 mm to 10 mm, and preferably 2 mm to 8 mm.

[0038] As described above, according to the battery module of the present disclosure, the accommodation section of the laminated battery includes an exhaust section, and the battery case is filled with a predetermined amount of molded resin, so that an exhaust path for discharging gas from the laminated battery in the event of an abnormality can be secured while preventing the spread of fire. [Explanation of symbols]

[0039] 1 battery module, 10 laminated battery, 12 partition wall, 14 battery case, 16 lid, 20 molded resin, 22 storage section, 22a exhaust section, 22b main body section, 23 sealing section, 24 first electrode lead, 26 second electrode lead, M upper surface of molded resin

Claims

1. A battery case and a plurality of laminate batteries housed in the battery case; Each of the plurality of laminate batteries has an electrode body, a housing portion that houses the electrode body, and a sealing portion that seals the periphery of the housing portion, the housing portion includes an exhaust portion and a main body portion, The battery case is filled with a molding resin except for the tip of the exhaust portion.

2. The battery module according to claim 1 , wherein the main body is embedded in the molding resin.

3. The battery module according to claim 1 , wherein each of the plurality of laminate batteries has a plurality of the housing portions.

4. The battery module according to claim 3 , wherein the exhaust portion of the housing portion is provided so as to protrude from one side of the electrode body of the main body portion in the axial direction of the electrode body.

5. 5. The battery module according to claim 1, wherein an exhaust path for gas discharged from the electrode body when a sealed portion of a laminated battery on an extension line of the tip of the exhaust portion is opened is formed between the inner surface of the battery case and the upper surface of the molded resin filled in the battery case.

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