Battery pack and electric device

Abstract

The utility model provides a battery pack and an electric device. The battery pack comprises a box body, a plurality of battery monomers and a heat management component, the box body comprises a lower box body and a bottom plate, and a first containing cavity is defined by the lower box body and the bottom plate. The plurality of single batteries are arranged in the first accommodating cavity of the box body; the thermal management component is disposed between the battery cells and the bottom plate. The lower box body comprises a step structure, the step structure comprises a first step surface and a second step surface which have a height difference, the first step surface is connected with the heat management component, and the second step surface is connected with the bottom plate. The heat management component 2 and the bottom plate 4 are connected with different step surfaces of the step structure 31 of the lower box body 3, compared with the condition that the heat management component 2 and the bottom plate 4 are connected with the same position of the lower box body 3, the bottom plate 4 only needs a small pit punching depth H, the process is simple, and damage is not prone to occurring.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly provides a battery pack and an electric device. Background Art

[0002] In an electric device (such as an electric vehicle), the battery system is one of the key systems, and the power battery pack (hereinafter referred to as the battery pack) is the core component of the battery system. The power battery pack includes a box body and battery cells and a cold plate inside the box body. The box body includes a lower box body and a bottom plate. The cold plate is located at the bottom of the battery cells, and both the cold plate and the bottom plate are connected to the lower box body. The punching pits on the bottom plate are too large, the processing difficulty is high, and the corners are prone to breakage. Summary of the Utility Model

[0003] In order to solve the problems of high processing difficulty and easy breakage of the bottom plate preparation process, the utility model provides a battery pack, which is characterized in that the battery pack includes: a box body including a lower box body and a bottom plate, the lower box body and the bottom plate enclosing an accommodation cavity; a plurality of battery cells arranged in the accommodation cavity; and a thermal management component arranged between the battery cells and the bottom plate; the lower box body includes a stepped structure, the stepped structure including a first stepped surface and a second stepped surface with a height difference, the first stepped surface being connected to the thermal management component, and the second stepped surface being connected to the bottom plate.

[0004] If the thermal management component and the bottom plate are connected to the same position of the lower box body, the punching pits on the bottom plate need to be designed very large, which is difficult to implement in terms of process and is prone to breakage. In the utility model, the thermal management component and the bottom plate are connected to different stepped surfaces of the stepped structure of the lower box body, so that the bottom plate only needs relatively small punching pits, the process is simple and not prone to breakage.

[0005] In an alternative technical solution of the utility model, the thermal management component and the first stepped surface are welded. Because when there is no need to disassemble the thermal management component, the welding process is simpler.

[0006] In an alternative technical solution of the utility model, the thermal management component and the first stepped surface are welded by friction stir welding. Compared with the conventional welding method, friction stir welding has low cost, high production efficiency and environmental friendliness.

[0007] In an alternative technical solution of the utility model, the width L1 of the first stepped surface satisfies: 17mm ≤ L1 ≤ 30mm.

[0008] In an alternative technical solution of the present utility model, the height difference D1 between the first step surface and the second step surface satisfies: 3 mm ≤ D1 ≤ 15 mm. Further, the height difference D1 between the first step surface and the second step surface can satisfy: 4 mm ≤ D1 ≤ 10 mm. By setting the height difference between the first step surface and the second step surface within the above numerical range, the punching depth of the bottom plate can be made smaller, the process is simple, and the size between the bottom plate and the thermal management component is not too large, avoiding energy density loss of the battery pack.

[0009] In an alternative technical solution of the present utility model, the bottom plate and the second step surface are connected by bolts, and the lower box body is provided with a second accommodation cavity above the second step surface, and the second accommodation cavity accommodates the bolts. By allowing the rod of the bolt to extend into the second accommodation cavity above the second step surface, compared with the case of being exposed through the bottom plate, the outer surface of the battery pack can be ensured to be flatter.

[0010] In an alternative technical solution of the present utility model, a sealing gasket is provided between the second step surface and the bottom plate.

[0011] In an alternative technical solution of the present utility model, an insulating layer is provided on the thermal management component.

[0012] In an alternative technical solution of the present utility model, the battery cell and the thermal management component are bonded by a thermal conductive adhesive.

[0013] The present utility model further provides an electrical device, including the above battery pack. Description of the Drawings

[0014] Figure 1 is a schematic diagram of the battery pack;

[0015] Figure 2 is Figure 1 a cross-sectional view of the battery pack;

[0016] Figure 3 is Figure 2 a partial enlarged view of;

[0017] Reference Signs

[0018] Battery cell 1;

[0019] Thermal management component 2;

[0020] Lower box body 3;

[0021] Step structure 31, end plate 32, second accommodation cavity 33;

[0022] First step surface 311, second step surface 312;

[0023] Bottom plate 4;

[0024] Crossbeam 5;

[0025] Bolt 6;

[0026] Gasket 7. Specific implementation manner

[0027] The optional implementation manners of the present utility model will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principle of the present utility model and are not intended to limit the protection scope of the present utility model.

[0028] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "distance", "width", "thickness", "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.

[0029] In the description of the present utility model, the terms "first", "second", "third", "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. In the description of the present utility model, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0030] In addition, it should also be noted that in the description of the present utility model, unless otherwise clearly specified and limited, the terms "set" and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can also be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0031] As Figures 1-3 shown, the present utility model provides a battery pack, which includes a box body, a plurality of battery cells 1 and a thermal management component 2. The box body includes a lower box body 3 and a bottom plate 4, and the lower box body 3 and the bottom plate 4 enclose a first accommodation cavity. A plurality of battery cells 1 are arranged in the first accommodation cavity of the box body. The thermal management component 2 is arranged between the battery cells 1 and the bottom plate 4. The lower box body 3 includes a step structure 31, and the step structure 31 includes a first step surface 311 and a second step surface 312 with a height difference. The first step surface 311 is connected to the thermal management component 2, and the second step surface 312 is connected to the bottom plate 4.

[0032] If the thermal management component 2 and the bottom plate 4 are connected to the same position of the lower box body 3, the depth of the punching pit of the bottom plate 4 needs to be designed to be very large, which is difficult to achieve in terms of process and the corner positions of the punching pit are prone to breakage. In the present utility model, the thermal management component 2 and the bottom plate 4 are connected to different step surfaces of the step structure 31 of the lower box body 3, so that the bottom plate 4 only needs a relatively small punching pit depth H, the process is simple and it is not easy to break.

[0033] In this application, the battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, a magnesium-ion battery cell, etc., and the embodiments of this application do not limit this. The battery cell may be in a cylindrical shape, a flat shape, a cuboid shape or other shapes, etc., and the embodiments of this application do not limit this either.

[0034] The battery cell includes an electrode assembly and an electrolyte. The electrode assembly includes a positive electrode plate, a negative electrode plate and a separator. The battery cell mainly operates by the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer is coated on the surface of the positive electrode current collector; the positive electrode current collector includes a positive electrode coating area and a positive electrode tab connected to the positive electrode coating area. The positive electrode coating area is coated with a positive electrode active material layer, and the positive electrode tab is not coated with a positive electrode active material layer. Taking a lithium-ion battery as an example, the material of the positive electrode current collector may be aluminum, and the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material may be lithium cobaltate, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer is coated on the surface of the negative electrode current collector; the negative electrode current collector includes a negative electrode coating area and a negative electrode tab connected to the negative electrode coating area. The negative electrode coating area is coated with a negative electrode active material layer, and the negative electrode tab is not coated with a negative electrode active material layer. The material of the negative electrode current collector may be copper, and the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material may be carbon or silicon, etc. The material of the separator may be PP (polypropylene) or PE (polyethylene), etc.

[0035] As Figure 1 shown, in an alternative embodiment of the present utility model, a cross beam 5 and a longitudinal beam are further provided in the box body. The cross beam 5 and the longitudinal beam are cross-shaped, dividing the accommodation cavity in the box body into four small accommodation cavities, and a plurality of battery cells 1 are arranged in each accommodation cavity. The lower box body 3 further includes an end plate 32. Along the arrangement direction of the end plate 32 and the cross beam 5, a foam is further provided between adjacent battery cells 1. The surface of the battery cell 1 with the largest area faces the end plate 32 for placement. As Figures 1-3 shown, the lower box body 3 is a hollow frame surrounded by four sides, and this hollow frame is connected to the box cover, the thermal management component 2, the cross beam 5 and the bottom plate 4, etc.

[0036] As Figure 3As shown, in an alternative embodiment of the present utility model, the thermal management component 2 is welded to the first stepped surface 311. Since there is no need to disassemble the thermal management component 2, the welding process is simpler. Of course, the thermal management component 2 and the first stepped surface 311 can also be connected by bolts.

[0037] As Figure 3 As shown, in an alternative embodiment of the present utility model, the thermal management component 2 and the first stepped surface 311 are welded by friction stir welding. Compared with conventional welding methods, friction stir welding has low cost, high production efficiency, and is environmentally friendly.

[0038] As Figure 3 As shown, in an alternative embodiment of the present utility model, the width L1 of the first stepped surface 311 satisfies: 17mm ≤ L1 ≤ 30mm. Specifically, the width L1 of the first stepped surface 311 can be 17mm, 18mm, 24mm, 28mm, 30mm. The height difference D1 between the first stepped surface 311 and the second stepped surface 312 satisfies: 3mm ≤ D1 ≤ 15mm. Further, the height difference D1 between the first stepped surface 311 and the second stepped surface 312 can satisfy: 4mm ≤ D1 ≤ 10mm. Specifically, D1 can be 3mm, 4mm, 6mm, 10mm, 15mm. Setting the height difference between the first stepped surface 311 and the second stepped surface 312 within the above numerical range can not only make the pit depth of the bottom plate 4 smaller and the process simpler, but also ensure that the size between the bottom plate 4 and the thermal management component 2 is not too large, avoiding energy density loss of the battery pack. Setting the width of the first stepped surface 311 within the above numerical range can not only ensure sufficient welding width and welding firmness, but also avoid the first stepped surface 311 being too wide and occupying too much space. In this embodiment, there is only one step between the first stepped surface 311 and the second stepped surface 312. Multiple steps can also be provided between the first stepped surface 311 and the second stepped surface 312, as long as the height difference between the two stepped surfaces that can be respectively connected to the thermal management component 2 and the bottom plate 4 is appropriate.

[0039] As Figure 3 As shown, in an alternative embodiment of the present utility model, the bottom plate 4 and the second stepped surface 312 are connected by bolts 6. The lower box body 3 is provided with a second accommodation cavity 33 above the second stepped surface 312, and the second accommodation cavity 33 accommodates the bolts 6. Letting the rod of the bolt 6 extend into the second accommodation cavity 33 above the second stepped surface 312 can ensure that the outer surface of the battery pack is flatter compared to the case where it penetrates through the bottom plate 4 and is exposed. And the setting of the second accommodation cavity 33 can also make the lower box body 3 lighter in mass, reducing the weight of the entire battery pack. As Figure 3 As shown, a gasket 7 is also provided between the bottom plate 4 and the second stepped surface 312 to ensure the connection is sealed.

[0040] As Figure 3As shown, in an alternative embodiment of the present utility model, an insulating layer is provided on the thermal management component 2. The battery cell 1 and the thermal management component 2 are bonded by a thermal conductive adhesive. The provision of the insulating layer can prevent abnormal electrical connection between the components in the battery pack and the thermal management component 2. The provision of the thermal conductive adhesive improves the heat exchange efficiency between the battery cell 1 and the thermal management component 2, and also improves the stability of the overall structure of the battery cell 1 and the thermal management component 2. A foam can also be provided between the thermal management component 2 and the bottom plate 4. When the bottom of the battery pack is impacted, the foam can play a buffering role to prevent the thermal management component 2 from being damaged.

[0041] The present utility model also provides an electrical device. The electrical device of the present utility model includes the battery pack of the alternative embodiment. The electrical device can be, but is not limited to, a mobile phone, a tablet computer, a laptop computer, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, and so on. Among them, the electric toy can include a fixed or mobile electric toy, such as a game console, an electric vehicle toy, an electric ship toy, and an electric aircraft toy, etc. The spacecraft can include an airplane, a rocket, a space shuttle, and a spaceship, etc.

[0042] So far, the technical solution of the present utility model has been described in conjunction with the alternative embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present utility model is obviously not limited to these specific embodiments. Without departing from the principle of the present utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present utility model.

Claims

1. A battery pack, characterized in that: The battery pack comprises: The box body comprises a lower box body and a bottom plate, wherein the lower box body and the bottom plate form a first accommodating cavity; A plurality of battery cells are disposed in the first accommodation cavity; and A thermal management component is disposed between the battery cell and the base plate; The lower box body includes a step structure, and the step structure includes a first step surface and a second step surface with a height difference, the first step surface is connected to the thermal management component, and the second step surface is connected to the bottom plate.

2. The battery pack according to claim 1, characterized in that: The thermal management component and the first step surface are welded.

3. The battery pack according to claim 2, characterized in that: The thermal management component and the first step surface are welded by friction stir welding.

4. The battery pack according to claim 2, characterized in that: The width L1 of the first step surface satisfies: 17 mm ≤ L1 ≤ 30 mm.

5. The battery pack according to claim 1, wherein: A height difference D1 between the first step surface and the second step surface satisfies: 3 mm ≤ D1 ≤ 15 mm.

6. The battery pack according to claim 5, characterized in that: A height difference D1 between the first step surface and the second step surface satisfies: 4 mm ≤ D1 ≤ 10 mm.

7. The battery pack according to claim 1, characterized in that: The bottom plate and the second step surface are connected by bolts, and the lower box body is provided with a second accommodating cavity above the second step surface, and the second accommodating cavity accommodates the bolts.

8. The battery pack according to claim 7, characterized in that: A sealing gasket is arranged between the second step surface and the bottom plate.

9. The battery pack according to claim 1, characterized in that: An insulating layer is arranged on the heat management component.

10. The battery pack according to claim 1, wherein: The battery cell and the thermal management component are bonded by thermal conductive adhesive.

11. An electrical device, characterized in that: The electrical device comprises the battery pack according to any one of claims 1 to 10.

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