Battery pack and electric device

Abstract

The application discloses a battery pack and an electric device, and relates to the technical field of battery packs. The battery pack comprises a box body, a battery pack and a separation component. The box body comprises a bottom plate and a beam body which is arranged to protrude from the bottom plate along a third direction, and the beam body extends along a second direction. The battery pack is arranged on one side of the beam body along a first direction, and the battery pack comprises a plurality of single batteries which are arranged along the first direction. The separation component comprises a first separation piece and a second separation piece. The first separation piece is arranged between two adjacent single batteries, and the second separation piece is arranged at at least one end of the battery pack along the first direction and is located between the beam body and the battery pack. The thickness of the first separation piece along the first direction is greater than the thickness of the second separation piece along the first direction. The battery pack is designed by differentiating the thickness of the separation piece to match the size requirement of the buffer space of the single battery at different positions, thereby improving the consistency of the surface pressure of the single battery at different positions.

Description

Technical Field

[0001] This invention relates to the field of battery pack technology, and more particularly to a battery pack and an electrical device. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the demand for energy density and cycle life of power batteries continues to increase. The stress state of the battery during long-term charge-discharge cycles will affect the stability of battery performance and its service life.

[0003] Currently, in existing power battery designs, multiple individual cells are closely arranged to form a battery pack, and a standardized fixing structure is used to limit and secure the individual cells. During long-term cycling, the cells in the middle are compressed by the two adjacent cells, resulting in greater stress, while the cells at the ends are only compressed by the cells on one side, resulting in relatively less stress. This leads to inconsistent surface pressures between cells at different positions. This difference in surface pressure causes asynchronous expansion and contraction deformation between the end and middle cells, leading to uneven aging rates and increased differences in capacity decay, thus affecting the stability and lifespan of the power battery. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a battery pack that improves the consistency of surface pressure on individual battery cells at different locations by different designing the thickness of the separators to match the buffer space requirements of individual cells at different locations.

[0005] The present invention also proposes an electrical device having the above-mentioned battery pack.

[0006] A battery pack according to a first aspect of the present invention includes: The box body includes a base plate and a beam that protrudes from the base plate along the third direction, the beam extending along the second direction; A battery pack, wherein the battery pack is disposed on one side of the beam along the first direction, and the battery pack includes a plurality of individual cells arranged along the first direction; A separation assembly, comprising a first separator and a second separator, wherein the first separator is disposed between two adjacent individual cells, and the second separator is disposed at at least one end of the battery pack along the first direction and located between the beam and the battery pack; Wherein, the thickness of the first separator along the first direction is greater than the thickness of the second separator along the first direction.

[0007] The battery pack according to embodiments of the present invention has at least the following beneficial effects: This application reduces the risk of individual cells squeezing each other when they expand by setting separators between them to reserve buffer space. By differentiating the thickness of the first and second separators to match the buffer space requirements of the separators at different locations, the consistency of the surface pressure of individual cells at different locations is improved, the performance degradation difference caused by long-term uneven surface pressure of individual cells at different locations is reduced, and the overall performance consistency of the battery pack is improved, thus extending the cycle life and stability of the battery pack.

[0008] According to some embodiments of the present invention, the thickness of the first separator along the first direction is at least twice the thickness of the second separator along the first direction.

[0009] According to some embodiments of the present invention, the first separator includes a first frame having a first cavity, and the first cavity having a first opening and a second opening formed at its two ends along the first direction, respectively. The first opening and the second opening are respectively positioned facing the corresponding side of the individual battery cell.

[0010] According to some embodiments of the present invention, the first separator further includes a first buffer portion disposed in the first cavity and dividing the first cavity into a first deformation space and a second deformation space arranged along the first direction. The first deformation space is in communication with the first opening, and the second deformation space is in communication with the second opening.

[0011] According to some embodiments of the present invention, the first frame includes a first side and a second side disposed opposite to each other along the first direction, the first buffer includes a third side and a fourth side disposed opposite to each other along the first direction, and the first separator further includes an encapsulation film, wherein the first side, the second side, the third side and the fourth side are all covered with the encapsulation film; The first separator abuts against the adjacent individual battery cell via the encapsulation film.

[0012] According to some embodiments of the present invention, the encapsulation film includes a first sub-film and a second sub-film, the first sub-film covering the first side and the third side, and the second sub-film covering the second side and the fourth side.

[0013] According to some embodiments of the present invention, the second separator includes a second frame and a second buffer portion, the second frame having a second cavity, and the second cavity having a third opening and a fourth opening formed at both ends along the first direction, respectively; The second buffer portion is disposed in the second cavity and closes the third opening, while the fourth opening is open toward the battery pack.

[0014] According to some embodiments of the present invention, the first separator includes a first frame and a first buffer portion disposed in the first frame; the first frame has a first side perpendicular to the first direction, the first buffer portion has a third side perpendicular to the first direction and close to the first side, the second frame has a fifth side perpendicular to the first direction, and the second buffer portion has a sixth side perpendicular to the first direction and close to the fifth side. Wherein, the distance from the first side to the third side along the first direction is greater than the distance from the fifth side to the sixth side along the first direction.

[0015] According to some embodiments of the present invention, the elastic coefficients of the first buffer portion and the second buffer portion are different.

[0016] According to some embodiments of the present invention, the separator assembly further includes an end plate disposed on the side of the second separator facing away from the battery pack along the first direction, and connected to the second separator and the beam body respectively.

[0017] An electrical device according to a second aspect of the present invention includes a battery pack as described in any of the above embodiments.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a top view of the battery pack according to an embodiment of the present invention; Figure 2 This is an exploded schematic diagram of the battery pack according to an embodiment of the present invention; Figure 3 for Figure 1 A partially enlarged schematic diagram of the cross section along the AA direction; Figure 4 This is a cross-sectional view of the first separator according to an embodiment of the present invention; Figure 5 This is a cross-sectional view of the second separator and end plate according to an embodiment of the present invention; Figure 6 This is an exploded view of the end of the battery pack according to an embodiment of the present invention; Figure 7 This is an exploded view of the first separator in an embodiment of the present invention.

[0020] Figure label: First direction X; Second direction Y; Third direction Z; Battery pack 100; Individual cell 111; Separator component 200; First separator 210; first frame 211; first side 2111; second side 2112; first buffer 212; third side 2121; fourth side 2122; first cavity 213; first opening 2131; second opening 2132; first deformation space 2133; second deformation space 2134; encapsulation film 214; first sub-film 2141; second sub-film 2142; Second partition 220; second frame 221; fifth side 2211; second buffer 222; sixth side 2221; second cavity 223; fourth opening 2232; end plate 230; Box body 300; bottom plate 310; beam 320. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0025] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0026] With the rapid development of the new energy vehicle industry, the demand for energy density and cycle life of power batteries continues to increase. The stress state of the battery during long-term charge-discharge cycles will affect the stability of battery performance and its service life.

[0027] Currently, in existing power battery designs, multiple individual cells are closely arranged to form a battery pack, and a standardized fixing structure is used to limit and fix the individual cells. During long-term cycling, the cells in the middle are compressed by the two adjacent cells, resulting in greater stress, while the cells at the ends are only compressed by the cells on one side, resulting in relatively less stress. This leads to inconsistent surface pressures of cells at different positions. This difference in surface pressure causes asynchronous expansion and contraction deformation between the end and middle cells, leading to uneven aging rates and increased differences in capacity decay, thus affecting the stability and lifespan of the power battery.

[0028] To address the aforementioned problems, this application proposes a battery pack. For ease of description, the battery pack is defined as having a first direction X, a second direction Y, and a third direction Z that are mutually perpendicular. For example... Figure 1 and Figure 2 As shown, the battery pack includes a housing 300 and a battery pack 100. The housing 300 includes a base plate 310, a beam 320, etc., and defines a receiving cavity for accommodating the battery pack 100. The beam 320 is disposed within the receiving cavity and extends along the second direction Y. The battery pack includes at least one battery pack 100, which is located on one side of the beam 320 along the first direction X. The battery pack 100 includes a plurality of individual battery cells 111 arranged along the first direction X. It is understood that the battery pack may include one battery pack 100 or multiple battery packs 100. When multiple battery packs 100 are included, each battery pack 100 is arranged along the second direction Y.

[0029] It should be noted that during the charge-discharge cycle of the battery pack, individual cells 111 will expand and contract in volume due to electrochemical reactions and temperature changes. If two adjacent cells 111 in the same group are in direct contact, their expansion forces will be superimposed, thus exacerbating the stress concentration inside the battery pack 100. To allow space for the expansion of individual cells 111 and prevent them from squeezing each other, such as... Figure 2 and Figure 3 As shown, the battery pack of this application is further provided with a separating component 200. The separating component 200 includes a first separating member 210 and a second separating member 220. The number of first separating members 210 is usually multiple. Each first separating member 210 is disposed between two adjacent individual cells 111 in the same group and abuts against the two adjacent individual cells 111 respectively, so as to maintain a preset gap between the two adjacent individual cells 111, providing buffer space for the opposite expansion of the individual cells 111 on both sides and reducing mutual compression stress. The number of second separating members 220 is at least one, disposed at at least one end of the battery pack 100 along the first direction X, and located between the beam 320 and the battery pack 100, to maintain a preset gap between the beam 320 and the individual cells 111 at the end of the battery pack 100, thereby reserving buffer space for the unilateral expansion of the individual cells 111 at the end. Figure 3 In the embodiment shown, the separator 200 includes two second separators 220, and the battery pack 100 is provided with second separators 220 at both ends along the first direction X.

[0030] It is understandable that the first separator 210 and the second separator 220 can be plates made entirely of elastic material, attached to the side of the single battery cell 111, and elastically deformed to provide cushioning when the single battery cell 111 expands. Alternatively, the first separator 210 and the second separator 220 can be frame structures made of rigid material, with a cavity defined in the middle. The frame structure corresponds to the edge region of the side of the single battery cell 111, and the cavity corresponds to the central region of the side of the single battery cell 111. Since the edge region deforms less due to the constraint of the single battery cell 111 shell, the frame structure can stabilize the spacing between adjacent single batteries 111 and improve the structural stability of the battery pack 100; while the central region deforms more, the cavity can provide buffer space for the deformation of the central region. Furthermore, the first separator 210 and the second separator 220 can also be composite structures made of rigid and flexible materials, such as covering the surface of a rigid substrate with a flexible layer, or filling the cavity of a rigid frame with flexible material, to balance the requirements of structural rigidity and deformation buffering.

[0031] It should be noted that for separators at different locations within the same battery pack 100, the second separator 220 at the end only needs to provide buffer space for the expansion deformation of a single cell 111 on one side, while the first separator 210 in the middle needs to provide buffer space for the expansion deformation of cells 111 on both sides. Therefore, this application designs the thickness of the first separator 210 and the second separator 220 differently, making the thickness of the first separator 210 along the first direction X greater than the thickness of the second separator 220 along the first direction X. This ensures that the first separator 210 in the middle can reserve more sufficient buffer space between the two cells 111, while the second separator 220 at the end has sufficient buffer space while avoiding being too thick and affecting the overall structural compactness.

[0032] Based on the above, this application reduces the risk of mutual compression of individual cells 111 during expansion by providing separators between cells 111 to reserve buffer space. By differentiating the thickness of the first separator 210 and the second separator 220, the buffer space requirements of individual cells 111 at different locations are matched, thereby improving the consistency of surface pressure of individual cells 111 at different locations, reducing the performance degradation differences caused by long-term uneven surface pressure of individual cells 111 at different locations, and thus improving the overall performance consistency of the battery pack 100, extending the cycle life of the battery pack 100 and improving its stability.

[0033] Furthermore, the thickness of the first separator 210 along the first direction X is at least twice the thickness of the second separator 220 along the first direction X, so that the first separator 210 can fully absorb the expansion displacement of the individual cells 111 on both sides, thereby making the surface pressure on each individual cell 111 tend to be consistent.

[0034] In some embodiments, such as Figure 3 and Figure 4 As shown, the first separator 210 includes a first frame 211, which has a first cavity 213. The first cavity 213 has a first opening 2131 and a second opening 2132 formed at its two ends along the first direction X. The first opening 2131 and the second opening 2132 open towards the corresponding individual battery cells 111. It can be understood that when the individual battery cell 111 on one side of the first separator 210 expands, its casing deforms towards the first opening 2131 and extends into the first cavity 213, while the individual battery cell 111 on the other side deforms towards the second opening 2132 and extends into the first cavity 213, thus avoiding stress concentration caused by rigid contact between the individual batteries 111. It should be noted that the first frame 211 is positioned corresponding to the edge region of the side of the individual battery cell 111, and can be as follows: Figure 6The lattice-shaped frame structure shown provides stable structural support between two adjacent individual cells 111. The first cavity 213 is disposed in the central region of the side of the individual cell 111 to provide deformation buffer space in areas of severe expansion.

[0035] Furthermore, such as Figure 3 and Figure 4 As shown, the first separator 210 also includes a first buffer portion 212, which is made of a flexible material. The first buffer portion 212 is disposed in the first cavity 213 and divides the first cavity 213 into a first deformation space 2133 and a second deformation space 2134. The first deformation space 2133 and the second deformation space 2134 are arranged along a first direction X. The first deformation space 2133 communicates with the first opening 2131, and the second deformation space 2134 communicates with the second opening 2132. It can be understood that the first deformation space 2133 is used to accommodate the expansion of the single cell 111 on one side, and the second deformation space 2134 is used to accommodate the expansion of the single cell 111 on the other side. When the expansion of the single cell 111 is large, the single cell 111 extends into the deformation space on the corresponding side and undergoes elastic deformation with the first buffer portion 212, so as to further absorb the expansion deformation energy through the deformation of the first buffer portion 212 and restrain the excessive expansion of the single cell 111.

[0036] Furthermore, the first frame 211 includes a first side surface 2111 and a second side surface 2112 arranged opposite to each other along the first direction X, the first buffer portion 212 includes a third side surface 2121 and a fourth side surface 2122 arranged opposite to each other along the first direction X, and the first separator 210 further includes an encapsulation film 214, wherein the first side surface 2111, the second side surface 2112, the third side surface 2121, and the fourth side surface 2122 are all covered with the encapsulation film 214. It can be understood that the encapsulation film 214 can be a single sheet covering the outer surface of the first frame 211 and the first buffer portion 212, or it can be multiple independent sheets each covering a different side. The encapsulation film 214 is made of a high-temperature resistant and anti-aging material, and can provide protection for the first frame 211 and the first buffer portion 212. In addition, the encapsulation film 214 can cover the surfaces of the first frame 211 and the first buffer portion 212 that are in direct contact with the individual battery 111, so that the first separator 210 abuts against the adjacent individual battery 111 through the encapsulation film 214, avoiding mechanical scratches between the housing of the individual battery 111 and the separator, and can also serve as insulation between the individual batteries 111.

[0037] Furthermore, such as Figure 7As shown, the encapsulation film 214 includes a first sub-film 2141 and a second sub-film 2142. The first sub-film 2141 covers the first side 2111 and the third side 2121, and the second sub-film 2142 covers the second side 2112 and the fourth side 2122.

[0038] In some embodiments, such as Figure 5 and Figure 6 As shown, the second separator 220 includes a second frame 221 and a second buffer portion 222. The second frame 221 has a second cavity 223. The second cavity 223 has a third opening and a fourth opening 2232 formed at both ends along the first direction X. The third opening is located on the side closer to the beam 320, and the fourth opening 2232 is located on the side closer to the battery pack 100. The second buffer portion 222 is disposed inside the second cavity 223 and closes the third opening. The fourth opening 2232 is open toward the battery pack 100. Thus, when the outer side of the individual battery 111 at the end of the battery pack 100 expands, it can extend into the second cavity 223 through the fourth opening 2232 and be elastically blocked by the second buffer portion 222.

[0039] Furthermore, the expansion of the individual cells 111 in the middle of the battery pack 100 is often greater than that of the individual cells 111 at the ends. Therefore, the buffer spaces reserved in the first separator 210 and the second separator 220 are designed differently. Specifically, the first frame 211 has a first side 2111 perpendicular to the first direction X, the first buffer portion 212 has a third side 2121 perpendicular to the first direction X and close to the first side 2111, the second frame 221 has a fifth side 2211 perpendicular to the first direction X, and the second buffer portion 222 has a sixth side 2221 perpendicular to the first direction X and close to the fifth side 2211. The fifth side 2211 and the sixth side 2221 are spaced apart. Wherein, as... Figure 4 and Figure 5 As shown, the distance from the first side 2111 to the third side 2121 along the first direction X is greater than the distance from the fifth side 2211 to the sixth side 2221 along the first direction X. This means that the depth of the buffer space provided by the first separator 210 on one side is greater than the depth of the buffer space provided by the second separator 220, thereby matching the greater expansion requirements of the single cell 111 in the middle of the battery pack 100.

[0040] Furthermore, the first buffer portion 212 and the second buffer portion 222 have different elastic coefficients to match the difference in expansion force between the middle and end individual battery cells 111. The first buffer portion 212 can be made of materials such as foam, aerogel, or silicone, and the second buffer portion 222 can also be made of any of the aforementioned materials.

[0041] In some embodiments, the separator assembly 200 of this application further includes an end plate 230, which is disposed on the side of the second separator 220 opposite to the battery pack 100 along the first direction X, and is connected to the second separator 220 and the beam 320 respectively. The end plate 230 can be made of a high-strength, insulating material such as epoxy board, serving both a supporting and insulating function.

[0042] The second aspect of this application provides an electrical device, which includes a device body and a battery pack mentioned in any of the preceding embodiments. It should be noted that the electrical device can be a vehicle, a pure electric vehicle, or a hybrid vehicle, with the device body being the vehicle body and the battery pack connected to the vehicle body; the electrical device can also be an energy storage device, with the device body being a cabinet and the battery pack connected to the cabinet. The electrical device can also be other devices, which will not be listed here. It is understood that since the electrical device of this application includes all the technical solutions in the preceding embodiments, it should have the beneficial effects corresponding to those embodiments, which will not be elaborated further here.

[0043] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A battery pack having a first direction (X), a second direction (Y), and a third direction (Z) perpendicular to each other, characterized by, The battery pack (100) is arranged on one side of the beam body (320) along the first direction (X), and the battery pack (100) comprises a plurality of single batteries (111) arranged along the first direction (X). The battery pack (100) is arranged on one side of the beam body (320) along the first direction (X), and the battery pack (100) comprises a plurality of single batteries (111) arranged along the first direction (X). The first partition piece (210) is arranged between two adjacent single batteries (111), and the second partition piece (220) is arranged at least one end of the battery pack (100) along the first direction (X) and between the beam body (320) and the battery pack (100). The thickness of the first partition piece (210) along the first direction (X) is at least twice the thickness of the second partition piece (220) along the first direction (X). The thickness of the first partition piece (210) along the first direction (X) is at least twice the thickness of the second partition piece (220) along the first direction (X).

2. The battery pack of claim 1, wherein, The first partition piece (210) comprises a first frame body (211) having a first cavity (213), and two ends of the first cavity (213) along the first direction (X) respectively form a first open port (2131) and a second open port (2132).

3. The battery pack of claim 1, wherein, The first open port (2131) and the second open port (2132) are respectively arranged to open towards the corresponding side single battery (111). The first partition piece (210) further comprises a first buffer portion (212) arranged in the first cavity (213) and separating the first cavity (213) into a first deformation space (2133) and a second deformation space (2134) arranged along the first direction (X), the first deformation space (2133) being in communication with the first open port (2131), and the second deformation space (2134) being in communication with the second open port (2132).

4. The battery pack of claim 3, wherein, The first frame body (211) comprises a first side surface (2111) and a second side surface (2112) arranged opposite along the first direction (X), the first buffer portion (212) comprises a third side surface (2121) and a fourth side surface (2122) arranged opposite along the first direction (X), and the first partition piece (210) further comprises an encapsulation film (214), and the first side surface (2111), the second side surface (2112), the third side surface (2121) and the fourth side surface (2122) are all covered with the encapsulation film (214).

5. The battery pack of claim 4, wherein, The first partition piece (210) is in abutment with the adjacent single battery (111) through the encapsulation film (213). ​ 6. The battery pack of claim 5, wherein, The packaging film (214) comprises a first sub-film (2141) and a second sub-film (2142), the first sub-film (2141) is wrapped on the first side (2111) and the third side (2121), and the second sub-film (2142) is wrapped on the second side (2112) and the fourth side (2122).

7. The battery pack of claim 1, wherein, The second partition (220) comprises a second frame (221) and a second buffer portion (222), the second frame (221) has a second cavity (223), and two ends of the second cavity (223) along the first direction (X) are respectively provided with a third opening and a fourth opening (2232); The second buffer portion (222) is arranged in the second cavity (223) and closes the third opening, and the fourth opening (2232) is open towards the battery pack (100).

8. The battery pack of claim 7, wherein, The first partition (210) comprises a first frame (211) and a first buffer portion (212) arranged in the first frame (211); the first frame (211) has a first side (2111) perpendicular to the first direction (X), the first buffer portion (212) has a third side (2121) perpendicular to the first direction (X) and close to the first side (2111), the second frame (221) has a fifth side (2211) perpendicular to the first direction (X), and the second buffer portion (222) has a sixth side (2221) perpendicular to the first direction (X) and close to the fifth side (2211); The distance from the first side (2111) to the third side (2121) along the first direction (X) is greater than the distance from the fifth side (2211) to the sixth side (2221) along the first direction (X).

9. The battery pack of claim 8, wherein, The elastic coefficients of the first buffer portion (212) and the second buffer portion (222) are different.

10. The battery pack of claim 1, wherein, The partition assembly (200) further comprises an end plate (230) arranged on a side of the second partition (220) away from the battery pack (100) along the first direction (X) and connected with the second partition (220) and the beam body (320) respectively.

11. An electrical device, characterized by The battery pack comprises any one of claims 1-10.

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