Battery pack

Abstract

The present invention provides a battery pack comprising: a battery frame for accommodating battery modules; a cooling module which is disposed on one surface of the battery frame, and which cools the battery modules; a first cover which is disposed, with the battery frame therebetween, so as to be opposite to the cooling module, and which protects the battery frame and the cooling module; and a second cover which is disposed, with the cooling module therebetween, so as to be opposite to the battery frame, and which protects the battery frame and the cooling module, wherein the cooling module includes a cooling plate, which includes a channel through which a coolant flows, and a support plate for supporting the battery modules, each of the cooling plate and the support plate comprising 0.1-0.2 wt% of carbon (C), 1.8-2.9 wt% of manganese (Mn), 0.5-1.0 wt% of silicon (Si), phosphorus (P) in an amount greater than or equal to 0 wt% and less than 0.05 wt%, sulfur (S) in an amount greater than or equal to 0 wt% and less than 0.01 wt%, and the balance of iron (Fe) and other inevitable impurities.

Description

battery pack

[0001] The present invention relates to a battery pack for a vehicle that can ensure safety and rigidity while reducing weight.

[0002] Due to global warming, environmental regulations are being strengthened worldwide, and policies to reduce carbon dioxide emissions to prevent global warming are rapidly replacing existing internal combustion engine vehicles with eco-friendly vehicles, especially electric vehicles.

[0003] Electric vehicle batteries are typically located under the vehicle body. These batteries are densely packed to maximize space efficiency. Consequently, the batteries generate significant heat.

[0004] If excessive heat is generated in the battery and this heat is not effectively removed, the battery's performance may deteriorate, its lifespan may be shortened, and in severe cases, it may even lead to a fire accident.

[0005] Therefore, when designing batteries for electric vehicles, it is very important to effectively dissipate or cool this heat.

[0006] The cooling module of the battery pack, which includes the existing battery cooling module, uses aluminum, and the battery frame uses steel.

[0007] Therefore, to prevent cracks and the like when joining such dissimilar materials, the cooling module and frame were joined using fastening means such as bolts in limited locations.

[0008] Therefore, problems such as reduced safety and increased weight occurred.

[0009] The present invention is intended to solve various problems including the above-described problems, and according to one embodiment of the present invention, a vehicle battery pack can be provided that can ensure safety and rigidity while reducing weight.

[0010] However, these tasks are exemplary and the scope of the present invention is not limited thereby.

[0011] According to one aspect of the present invention, there is provided a battery frame for accommodating a battery module; a cooling module disposed on one side of the battery frame and cooling the battery module; a first cover disposed on an opposite side of the cooling module with respect to the battery frame and protecting the battery frame and the cooling module; And a second cover disposed on the opposite side of the battery frame based on the cooling module and protecting the battery frame and the cooling module; wherein the cooling module includes a cooling plate including a flow path through which a coolant flows, and a support plate supporting the battery module, and the cooling plate and the support plate each include carbon (C) of 0.1 wt% or more and 0.2 wt% or less, manganese (Mn) of 1.8 wt% or more and 2.9 wt% or less, silicon (Si) of 0.5 wt% or more and 1.0 wt% or less, phosphorus (P) of 0 or more and less than 0.05 wt%, sulfur (S) of 0 or more and less than 0.01 wt%, iron (Fe) as a remainder, and other unavoidable impurities.

[0012] According to one embodiment of the present invention, as described above, a vehicle battery pack can be provided that ensures safety and rigidity while reducing weight. Of course, the scope of the present invention is not limited by these effects.

[0013] FIG. 1 is an exploded perspective view of a battery pack according to one embodiment of the present invention.

[0014] Figure 2 is a perspective view schematically showing a cooling module according to one embodiment of the present invention.

[0015] FIG. 3 is a plan view showing a shape in which a cooling module and a battery frame are joined according to one embodiment of the present invention.

[0016] Figure 4 is a graph showing the results of a frontal compression strength test of one embodiment and a comparative example of the present invention.

[0017] Figure 5 is a graph showing the results of a rear compression strength test of one embodiment and a comparative example of the present invention.

[0018] Figure 6 is a graph showing the results of a lateral compression strength test of one embodiment and a comparative example of the present invention.

[0019] The thickness of the cooling plate and the thickness of the support plate may each be 0.3 mm or more and 1.2 mm or more.

[0020] The tensile strength of the cooling plate and the tensile strength of the support plate may each be 300 MPa or more and 800 MPa or less.

[0021] The above cooling plate and the above support plate can be welded to each other.

[0022] The battery frame includes a first strut extending in the longitudinal direction of the battery frame, and a second strut extending in the width direction of the battery frame, and the first strut and the second strut intersect each other to form a space for accommodating the battery module, and a first welded portion welding the first strut and the support plate may be positioned between the first strut and the support plate, and a second welded portion welding the second strut and the support plate may be positioned between the second strut and the support plate.

[0023] Hereinafter, the present invention will be described in detail. When describing the present invention, if it is determined that a detailed description of a related known technology or configuration may unnecessarily obscure the gist of the present invention, such detailed description will be omitted.

[0024] In the examples below, the terms first, second, etc. are not used in a limiting sense, but are used for the purpose of distinguishing one component from another.

[0025] In the examples below, singular expressions include plural expressions unless the context clearly indicates otherwise.

[0026] In the following examples, when various components such as layers, films, regions, and plates are said to be “on” other components, this includes not only cases where they are “directly on” other components, but also cases where other components are interposed between them.

[0027] For convenience of explanation, the sizes of components in the drawings may be exaggerated or reduced. For example, the sizes and thicknesses of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to what is shown.

[0028] In the following examples, terms such as “include” or “have” mean that a feature or component described in the specification is present, and do not preclude the possibility that one or more other features or components may be added.

[0029] In this specification, “A and / or B” refers to the case where it is A, or B, or both A and B. In addition, in this specification, “at least one of A and B” refers to the case where it is A, or B, or both A and B.

[0030] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0031] Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement them. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0032] FIG. 1 is an exploded perspective view of a battery pack according to one embodiment of the present invention, and FIG. 2 is a perspective view schematically showing a cooling module (100) according to one embodiment of the present invention.

[0033] Referring to FIGS. 1 and 2, a battery pack according to one embodiment may include a cooling module (100), a battery frame (200), and a case (300).

[0034] A battery frame (200) according to one embodiment may have a grid shape and may have a space capable of accommodating a battery module within the grid space.

[0035] That is, the battery frame (200) can serve to guide the position of the battery modules so that they can be placed spaced apart from each other.

[0036] The cooling module (100) can be placed on one side of the battery frame (200) and serve to cool the battery module.

[0037] Referring to FIG. 2, the cooling module (100) may include a cooling plate (120) including a flow path (125) through which a coolant flows, and a support plate (110) that is in contact with the battery frame (200) and can transfer heat generated from the battery module to the coolant.

[0038] That is, the cooling module (100) may be formed by welding a support plate (110) and a cooling plate (120).

[0039] At this time, a known welding method such as laser welding, spot welding, tailor welded blank welding, or brazing can be used.

[0040] The support plate (110) supports the battery module on one side of the battery frame (200) and may have a flat shape to contact the battery module and transfer heat generated in the battery module to the cooling plate (120).

[0041] A flow path (125) through which a coolant can flow may be formed in the cooling plate (120). In one embodiment, the flow path (125) may have an 'ㄹ' shape, or a shape in which 'n' and 'u' are alternately connected. However, the present invention is not limited thereto. The flow path (125) may have any shape as long as it can effectively transfer the heat transferred from the battery module by the support plate (110) to the coolant.

[0042] As shown in Fig. 2, when the support plate (110) and the cooling plate (120) are joined, a space or path through which the coolant can circulate can be created. In one embodiment, a path can be formed in the support plate (110) at a position corresponding to the path (125) of the cooling plate (120).

[0043] The coolant may include a material capable of absorbing heat. In one embodiment, the coolant may be cold air or water.

[0044] The support plate (110) and cooling plate (120) may each be made of steel.

[0045] In one embodiment, the support plate (110) and the cooling plate (120) may include carbon (C) of 0.1 wt% or more and 0.2 wt% or less, manganese (Mn) of 1.8 wt% or more and 2.9 wt% or less, silicon (Si) of 0.5 wt% or more and 1.0 wt% or less, phosphorus (P) of 0 wt% or more and less than 0.05 wt%, sulfur (S) of 0 wt% or more and less than 0.01 wt%, iron (Fe) as a remainder, and other unavoidable impurities.

[0046] The support plate (110) and the cooling plate (120) may have the same element content, but may have different element contents in some cases.

[0047] The thickness of the support plate (110) and the cooling plate (120) may be 0.3 mm or more and 1.2 mm or less, respectively. The support plate (110) and the cooling plate (120) may have the same thickness, but may have different thicknesses in some cases.

[0048] The tensile strength of the support plate (110) and the cooling plate (120) may be 300 MPa or more and 800 MPa or less, respectively. The support plate (110) and the cooling plate (120) may have the same tensile strength, but may have different tensile strengths depending on the case.

[0049] If the thickness of the support plate (110) and the cooling plate (120) exceeds 1.2 mm, the weight of the battery pack including them increases significantly, which may reduce the driving range of the vehicle when mounted on the vehicle. On the other hand, if the thickness is less than 0.3 mm, the rigidity that can ensure safety may not be secured.

[0050] If the tensile strength of the support plate (110) and the cooling plate (120) is less than 300 MPa, the safety of the battery pack cannot be guaranteed, and if the tensile strength exceeds 800 MPa, the shock absorption ability is reduced, so safety may actually decrease.

[0051] The support plate (110) and the cooling plate (120) must have the element contents as described above so that the tensile strength as described above, which can ensure safety, can be secured even at the thickness as described above.

[0052] In other words, it is possible to ensure safety by securing the desired tensile strength while drastically reducing the weight of the battery pack.

[0053] As described above, the cooling module (100) can be placed on one side of the battery frame (200).

[0054] In one embodiment, the battery frame (200) may also be made of steel.

[0055] In one embodiment, the battery frame (200) may include carbon (C) of 0.15 wt% or more and 0.3 wt% or less, manganese (Mn) of 1.4 wt% or more and 2.5 wt% or less, silicon (Si) of 0.09 wt% or more and 0.8 wt% or less, phosphorus (P) of 0 wt% or more and 0.05 wt% or less, sulfur (S) of 0 wt% or more and 0.01 wt% or less, iron (Fe) as a remainder, and other unavoidable impurities.

[0056] In one embodiment, the tensile strength of the battery frame (200) may be greater than or equal to 600 MPa and less than or equal to 1,800 MPa.

[0057] Since both the battery frame (200) and the cooling module (100) are made of steel, they can be joined using a welding method such as laser welding, spot welding, tailor welded blank welding, arc welding, or brazing.

[0058] FIG. 3 is a plan view showing the shape in which a cooling module (100) and a battery frame (200) are joined according to one embodiment of the present invention.

[0059] Referring to FIG. 3, the battery frame (200) may include a strut (210) that forms a grid-shaped space capable of accommodating a battery module.

[0060] The strut (210) may include a first strut (211) and a second strut (212) that intersect each other to form a space for accommodating a battery module.

[0061] The first strut (211) may extend in the longitudinal direction (e.g., x-axis direction) of the battery frame (200). The second strut (212) may be approximately orthogonal to the first strut (211) and may extend in the width direction (e.g., y-axis direction) of the battery frame (200).

[0062] The first strut (211) and the second strut (212) intersect each other to form a grid shape, and a battery module can be accommodated within the space formed thereby.

[0063] The first strut (211) and the second strut (212) can be in direct contact with the cooling module (100). Specifically, the first strut (211) and the second strut (212) can be in direct contact with the support plate (110) of the cooling module (100).

[0064] That is, the first strut (211) and the second strut (212) can be joined to the support plate (110) of the cooling module (100) by a method such as welding.

[0065] As shown in FIG. 3, a weld (400) may be positioned between the first strut (211) and the support plate (110), and between the second strut (212) and the support plate (110).

[0066] The welded portion (400) may be an area where the first strut (211) and the support plate (110), or the second strut (212) and the support plate (110) are welded using a welding method such as laser welding, spot welding, tailor welded blank welding, arc welding, or brazing.

[0067] In other words, a weld (400) that welds the first strut (211) and the support plate (110) may be positioned between the first strut (211) and the support plate (110), and a weld (400) that welds the second strut (212) and the support plate (110) may be positioned between the second strut (212) and the support plate (110).

[0068] As described above, when the strut (210) and the support plate (110) are joined by a method such as welding rather than a bolt fastening method, the rigidity can be improved, thereby increasing safety, and heat transfer from the battery module to the coolant can be made easier.

[0069] The case (300) may be a member that accommodates the cooling module (100) and the battery frame (200) to protect the cooling module (100) and the battery frame (200).

[0070] Referring again to FIG. 1, the case (300) may include a first cover (310) and a second cover (320).

[0071] The first cover (310) is positioned on the opposite side of the cooling module (100) with respect to the battery frame (200), so as to protect the cooling module (100) and the battery frame (200). In one embodiment, the first cover (310) may be an upper cover of the battery pack.

[0072] The second cover (320) may be placed on the opposite side of the battery frame (200) with respect to the cooling module (100) to protect the cooling module (100) and the battery frame (200). In one embodiment, the second cover (320) may be a lower cover of the battery pack.

[0073] The first cover (310) and the second cover (320) form the outer shape of the battery pack and can protect the materials accommodated inside.

[0074] The first cover (310) and the second cover (320) may each contain carbon (C) of 0.1 wt% or more and 0.15 wt% or less, manganese (Mn) of 0.3 wt% or more and 2.5 wt% or less, silicon (Si) of 0.03 wt% or more and 0.8 wt% or less, phosphorus (P) of 0 wt% or more and 0.05 wt% or less, sulfur (S) of 0 wt% or more and 0.01 wt% or less, and the remainder iron (Fe) and other unavoidable impurities.

[0075] In one embodiment, the tensile strength of the first cover (310) and the second cover (320) may be 200 MPa or more and 800 MPa or less, respectively.

[0076] Hereinafter, the structure and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way.

[0077] Experimental example

[0078] Below, the present invention will be described in more detail through experimental examples. However, the following experimental examples are intended to further illustrate the present invention, and the scope of the present invention is not limited by these examples. Those skilled in the art may appropriately modify or alter the following experimental examples within the scope of the present invention.

[0079] Example

[0080] A battery pack including a cooling module, a battery frame, and a case formed by welding a support plate having a thickness of 0.8 mm and a tensile strength of 600 MPa and a cooling plate having a thickness of 0.6 mm and a tensile strength of 600 MPa was manufactured.

[0081] The cooling plate contained 0.15 wt% carbon (C), 2.5 wt% manganese (Mn), 0.8 wt% silicon (Si), 0.05 wt% phosphorus (P), 0.01 wt% sulfur (S), the remainder iron (Fe) and other unavoidable impurities, and the support plate contained 0.15 wt% carbon (C), 2.5 wt% manganese (Mn), 0.8 wt% silicon (Si), 0.05 wt% phosphorus (P), 0.01 wt% sulfur (S), the remainder iron (Fe) and other unavoidable impurities.

[0082] The battery pack according to the embodiment had a weight of 22.3 kg.

[0083] Comparative example

[0084] The battery pack according to the comparative example was manufactured in the same manner as in the example, except that the cooling plate was manufactured from aluminum with a thickness of 1.5 mm and the support plate was manufactured from aluminum with a thickness of 3.0 mm. The battery pack according to the comparative example had a weight of 25.6 kg.

[0085] It can be seen that the embodiment is capable of reducing weight compared to the comparative example because the thickness of the cooling plate and support plate constituting the cooling module is small.

[0086] Compressive strength test

[0087] FIG. 4 is a graph showing the results of a frontal compression strength test of an embodiment of the present invention and a comparative example, FIG. 5 is a graph showing the results of a rearal compression strength test of an embodiment of the present invention and a comparative example, and FIG. 6 is a graph showing the results of a side compression strength test of an embodiment of the present invention and a comparative example.

[0088] Specifically, FIGS. 4 to 6 are graphs showing the magnitude of the load according to the deformation, i.e. displacement, applied to the front, rear, and side of the battery pack according to the embodiment and comparative example.

[0089] Referring to the results of the frontal compression strength test in Fig. 4, when the target load of 200 kN was reached, the displacement in the example was 11 mm, which was good.

[0090] Additionally, the maximum load shown in the example was 220 kN at 18 mm, and the maximum load shown in the comparative example was 222.6 kN at 17.2 mm.

[0091] That is, although the embodiment was approximately 13% lighter in weight than the comparative example, the maximum load that could be withstood in a frontal collision was measured to be similar to that of the comparative example.

[0092] In addition, since the maximum load that can be withstood is measured to be large when the displacement is larger, that is, when the deformation is large, it can be seen that the embodiment is safer than the comparative example.

[0093] Referring to the results of the rear compression strength test in Fig. 5, the maximum load shown in the example was 238.8 kN at 72.4 mm, and the maximum load shown in the comparative example was 227.8 kN at 76.1 mm.

[0094] That is, although the embodiment was approximately 13% lighter in weight than the comparative example, the maximum load that could be withstood in a rear collision was 4.8% higher than that of the comparative example.

[0095] Referring to the lateral compression strength test results of Fig. 6, when the target load of 200 kN was reached, the displacement was 20 mm, which was good for the example.

[0096] Additionally, the maximum load shown in the example was 228.3 kN at 30.5 mm, and the maximum load shown in the comparative example was 228.6 kN at 29.5 mm.

[0097] That is, although the embodiment is about 13% lighter in weight than the comparative example, the maximum load that can be withstood in a side collision was measured to be similar to that of the comparative example.

[0098] Additionally, there was little deformation within the module space in all front, back and side compressive strength tests.

[0099] Therefore, the embodiment was able to ensure safety and rigidity while reducing weight.

[0100] The embodiments of the present invention are merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

Claims

1. Battery frame that accommodates the battery module; A cooling module disposed on one side of the battery frame and cooling the battery module; A first cover positioned on the opposite side of the cooling module based on the battery frame and protecting the battery frame and the cooling module; and A second cover positioned on the opposite side of the battery frame based on the cooling module and protecting the battery frame and the cooling module; Including, The cooling module includes a cooling plate including a channel through which a coolant flows, and a support plate supporting the battery module. A battery pack, wherein the cooling plate and the support plate each contain carbon (C) of 0.1 wt% or more and 0.2 wt% or less, manganese (Mn) of 1.8 wt% or more and 2.9 wt% or less, silicon (Si) of 0.5 wt% or more and 1.0 wt% or less, phosphorus (P) of 0 wt% or more and less than 0.05 wt%, sulfur (S) of 0 wt% or more and less than 0.01 wt%, and the remainder iron (Fe) and other unavoidable impurities.

2. In paragraph 1, A battery pack, wherein the thickness of the cooling plate and the thickness of the support plate are each 0.3 mm or more and 1.2 mm or more.

3. In paragraph 1, A battery pack, wherein the tensile strength of the cooling plate and the tensile strength of the support plate are each 300 MPa or more and 800 MPa or less.

4. In paragraph 1, A battery pack wherein the cooling plate and the support plate are welded to each other.

5. In paragraph 1, The battery frame includes a first strut extending in the longitudinal direction of the battery frame, and a second strut extending in the width direction of the battery frame, The first strut and the second strut intersect each other to form a space for accommodating the battery module, Between the first strut and the support plate, a first welded portion is positioned where the first strut and the support plate are welded, A battery pack, wherein a second welded portion is positioned between the second strut and the support plate, wherein the second strut and the support plate are welded.

6. In paragraph 1, The above battery frame is a battery pack containing carbon (C) of 0.15 wt% or more and 0.3 wt% or less, manganese (Mn) of 1.4 wt% or more and 2.5 wt% or less, silicon (Si) of 0.09 wt% or more and 0.8 wt% or less, phosphorus (P) of 0 wt% or more and 0.05 wt% or less, sulfur (S) of 0 wt% or more and 0.01 wt% or less, iron (Fe) as a remainder, and other unavoidable impurities.

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