Battery monomer, battery pack and power device

Abstract

The utility model discloses a single battery, a battery pack and a power device, the single battery comprises a shell, a battery pack and a battery pack, the shell is provided with an accommodating cavity and an opening communicated with the accommodating cavity; the inner shell is arranged in the containing cavity, and a cavity is formed in the inner shell; and the pole group is wound in the cavity, and the inner peripheral wall of the inner shell is attached to the outer peripheral wall of the pole group. According to the battery monomer disclosed by the utility model, the inner shell is arranged between the outer shell and the pole group, so that the safety of the battery cell in the whole life cycle is effectively improved, the phenomenon that the arc area of the pole group is torn when the battery cell is in a thermal runaway state is prevented, and the fire risk caused by the thermal runaway of the battery cell is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of power device manufacturing, in particular to a battery monomer, a battery pack and a power device. Background Art

[0002] It is pointed out in the relevant technology that lithium-ion batteries are widely used in consumer electronics, new energy vehicles, energy storage and other fields. In terms of appearance, the mainstream lithium-ion batteries on the market are mainly divided into square and cylindrical types, which can be divided into winding and lamination according to the pole grouping method. Among them, the advantage of winding grouping is that its process flow is relatively simple, the manufacturing cost is low, and the grouping efficiency is high, which is why it is sought after by many lithium-ion battery manufacturers. But at the same time, its disadvantages are also obvious. Compared with lamination, the volume energy density of the battery cell is relatively lower, and the pole pieces wound into groups will inevitably have a large number of arc areas. These areas are affected by the deformation of the pole piece winding, and there is a large stress inside the material. At the end of the battery cell's life cycle and in a thermal runaway state, it may evolve into a weak area of ​​the pole group, which will affect the electrical performance and safety performance of the battery cell.

[0003] Lithium-ion batteries have a safety risk of thermal runaway under abuse conditions (including electrical abuse, mechanical abuse, and thermal abuse). When a battery cell experiences thermal runaway, on the one hand, the increase in temperature will cause the diaphragm to shrink, and the positive and negative electrodes of the battery will come into direct contact, resulting in an internal short circuit. On the other hand, at high temperatures, the electrolyte inside the battery cell will undergo a series of chemical reactions with the positive and negative electrodes. Both of these phenomena will cause a large amount of gas and heat to be generated inside the battery cell, which will in turn cause the pole piece to be impacted. The arc area of ​​the wound pole group is relatively weak due to the presence of stress, and is easily ruptured by the impact of gas during the exhaust process of the thermal runaway of the battery cell, which in turn causes the pole piece to break and be ejected from the explosion-proof valve port with the gas. When the battery cell is in thermal runaway, the pole piece usually carries sparks, which can easily ignite the flammable material generated by the thermal runaway of the battery cell, causing the battery cell to catch fire and explode.

[0004] The mainstream wound battery cells in the market currently have only one layer of mylar film wrapped on the surface of the electrode group as an insulating protective layer between the electrode group and the shell. The arc area on both sides of the electrode group is almost in point contact with the battery cell, and there is a large space between the bend of the electrode group and the shell, which exacerbates the uneven force on the pole piece in the arc area. This makes the pole piece in this area more likely to be broken by airflow impact when the battery cell is in thermal runaway. Utility Model Content

[0005] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides a battery cell with a high safety factor.

[0006] The utility model also provides a battery pack having the battery monomer.

[0007] The present utility model further provides a power device having the above battery pack.

[0008] The battery cell according to the first aspect of the present utility model includes: a housing, the housing is formed with a receiving cavity and an opening communicating with the receiving cavity; an inner housing, the inner housing is disposed in the receiving cavity, and a cavity is formed in the inner housing; a pole group, the pole group is wound and disposed in the cavity, and the inner peripheral wall of the inner housing is in mutual contact with the outer peripheral wall of the pole group.

[0009] According to the battery cell of the present utility model, by providing an inner housing between the outer housing and the pole group, the safety during the entire life cycle of the battery core is effectively improved, the phenomenon that the arc area of the pole group is torn under the condition of thermal runaway of the battery core is prevented, and the risk of fire caused by thermal runaway of the battery core is reduced.

[0010] In some embodiments, a plurality of through holes arranged at intervals are formed on the peripheral wall of the inner housing, and each through hole penetrates the peripheral wall of the inner housing in the thickness direction of the peripheral wall of the inner housing.

[0011] In some embodiments, the cross section of the inner peripheral wall of the inner housing is waist-shaped, and the cross section of the outer peripheral wall of the inner housing is rectangular.

[0012] In some embodiments, the width W of the arc area of the inner housing is at least 1 mm greater than the radius of the outermost arc area of the pole group.

[0013] In some embodiments, the length L of the inner housing is at least 5 mm less than the length of the outer housing, and / or the height of the inner housing is the same as the height of the receiving cavity of the outer housing.

[0014] In some embodiments, the diameter of the through hole is not greater than 5 mm.

[0015] In some embodiments, the thickness of the peripheral wall of the outer housing is in the range of 0.3 mm - 1 mm.

[0016] In some embodiments, the inner housing is formed as a high-temperature resistant insulating material part, and / or the outer housing is formed as an aluminum part or a steel part.

[0017] The battery pack according to the second aspect of the present utility model includes the battery cell according to the first aspect of the present utility model above.

[0018] According to the battery pack of the present utility model, by providing the battery cell of the first aspect above, the safety performance of the battery pack is improved, while ensuring the energy density of the battery pack, the risk of side tearing of the pole group when the battery cell undergoes thermal runaway is avoided, and the danger coefficient of the whole pack is reduced.

[0019] The power device according to the third aspect of the present utility model includes a battery pack according to the second aspect of the present utility model as described above.

[0020] By providing the battery pack according to the second aspect of the present utility model, the overall performance of the power device is improved, and the safety performance of the power device is enhanced.

[0021] Additional aspects and advantages of the present utility model will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the inner shell of a battery cell according to an embodiment of the present utility model;

[0023] Figure 2 is Figure 1 an assembly schematic diagram of the battery cell shown in

[0024] Figure 3 is Figure 2 a front view schematic diagram of the battery cell shown in

[0025] REFERENCE SIGNS:

[0026] 100, battery cell; 1, outer shell; 2, inner shell; 21, through hole; 22, second arc region; 3, electrode group; 31, first arc region. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Embodiments of the present utility model will be described in detail below. Examples of the embodiments are shown in the drawings, where 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 drawings are exemplary and are intended to explain the present utility model and should not be construed as limiting the present utility model.

[0028] Reference will be made below to Figures 1 - 3 describe the battery cell 100 according to an embodiment of the first aspect of the present utility model.

[0029] As Figure 1 shown, the battery cell 100 according to an embodiment of the first aspect of the present utility model includes: an outer shell 1, an inner shell 2, and an electrode group 3.

[0030] Specifically, the outer shell 1 is formed with a receiving cavity and an opening communicating with the receiving cavity. The inner shell 2 is disposed in the receiving cavity. A cavity is formed inside the inner shell 2. The electrode group 3 is wound and disposed in the cavity, and the inner peripheral wall of the inner shell 2 is in mutual fit with the outer peripheral wall of the electrode group 3. Thus, the structural design of the battery cell 100 is simple, effectively improving the safety of the battery cell 100.

[0031] The battery cell 100 according to the embodiment of the present utility model effectively improves the safety during the entire life cycle of the battery cell by arranging an inner shell 2 between the outer shell 1 and the electrode group 3, prevents the first arc region 31 of the electrode group 3 from being torn in the state of thermal runaway of the battery cell, and reduces the risk of fire caused by thermal runaway of the battery cell.

[0032] In some embodiments of the present utility model, as Figure 1 shown, a plurality of through holes 21 arranged at intervals are formed on the peripheral wall of the inner shell 2, and each through hole 21 penetrates the peripheral wall of the inner shell 2 in the thickness direction of the peripheral wall of the inner shell 2. The through holes 21 are used for exhausting gas during thermal runaway of the battery cell, and the through holes 21 help to reduce the weight of the inner shell 2, thereby reducing the overall weight of the battery cell 100.

[0033] In some embodiments of the present utility model, as Figure 1 shown, the cross-section of the inner peripheral wall of the inner shell 2 is waist-shaped, and the cross-section of the outer peripheral wall of the inner shell 2 is rectangular. In this way, the energy consumption can better fit the outer periphery of the electrode group 3. When the electrode group 3 undergoes thermal runaway, the risk of tearing of the first arc region 31 on the side of the electrode group 3 can be reduced.

[0034] In some embodiments of the present utility model, the width W of the second arc region 22 of the inner shell 2 is at least 1 mm greater than the radius of the outermost first arc region 31 of the electrode group 3. Specifically, the radius of the second arc region 22 of the inner shell 2 is the same as the radius of the outermost first arc region 31 of the electrode group 3, ensuring that the first arc region 31 of the electrode group 3 and the second arc region 22 of the inner shell 2 can be perfectly fitted after the battery cell is charged.

[0035] In some embodiments of the present utility model, the length L of the inner shell 2 is at least 5 mm less than the length of the outer shell 1, and / or the height of the inner shell 2 is the same as the height of the accommodation cavity of the outer shell 1. That is to say, the length L of the inner shell 2 is less than the length of the outer shell 1, and the height of the inner shell 2 is the same as the height of the inner side of the outer shell 1. Thereby, the influence on the welding of the periphery of the cover plate is avoided, the stability of the structure of the battery cell 100 is ensured, and the safety factor of the battery cell 100 is effectively improved.

[0036] In some embodiments of the present utility model, the diameter of the through hole 21 is not greater than 5 mm. For example, the diameter of the through hole 21 can be 5 mm, 4.9 mm, 4.8 mm, 4.7 mm, 4.6 mm, 4.5 mm, 4.4 mm, 4.3 mm, 4.2 mm, 4.1 mm, 4.0 mm, 3.9 mm, 3.8 mm, 3.7 mm, 3.6 mm, 3.5 mm, 3.4 mm, 3.3 mm, 3.2 mm, 3.1 mm, 3.0 mm, 2.9 mm, etc.

[0037] In some embodiments of the present utility model, the thickness of the peripheral wall of the outer shell 1 is in the range of 0.3 mm - 1 mm. AsFigure 2 As shown, the outer shell 1 is formed into a cuboid structure, and an opening is formed at one end of the accommodating cavity to facilitate the placement of the inner shell 2 and the electrode group 3 therein. Moreover, the shape of the accommodating cavity is the same as the external shape of the inner shell 2, ensuring that the outside of the inner shell 2 can be closely attached to the inside of the outer shell 1, thereby enhancing the safety of the battery cell 100.

[0038] For example, the thickness of the peripheral wall of the outer shell 1 can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, etc.

[0039] In some embodiments of the present invention, the inner shell 2 is formed into a high-temperature resistant insulating material part. Specifically, the material of the inner shell 2 can be mica, or an oxide material, or other high-temperature resistant insulating materials (at least 500 °C), and it is required to be a material with good chemical stability and electrochemical stability, high hardness, and not easily deformed, and / or the outer shell 1 is formed into an aluminum part or a steel part.

[0040] In summary, when the battery cell is fully charged, due to the intercalation of lithium ions, the material layer spacing increases, and the electrode group 3 expands in volume. The expanded electrode group 3 fits with the second arc area 22 of the inner shell 2, which can provide certain support for the arc weak area of the electrode group 3 to ensure uniform stress on the arc weak area of the electrode group 3 and improve the mechanical strength of the electrode plate. When the battery cell undergoes thermal runaway, due to the protective support of the inner shell 2, the risk of tearing in the first arc area 31 on the side of the electrode group 3 is greatly reduced, and the number of electrode plates with gas ejected through the explosion-proof valve is greatly reduced, and the risk of the battery cell catching fire due to thermal runaway also decreases accordingly.

[0041] The battery pack according to the second aspect embodiment of the present invention includes the battery cell 100 according to the first aspect embodiment of the present invention above.

[0042] The battery pack according to the embodiment of the present invention improves the safety performance of the battery pack by setting the battery cell 100 according to the first aspect embodiment above. While ensuring the energy density of the battery pack, it avoids the risk of tearing on the side of the electrode group 3 when the battery cell 100 undergoes thermal runaway and reduces the danger coefficient of the whole pack.

[0043] The power device according to the third aspect embodiment of the present invention includes the battery pack according to the second aspect embodiment of the present invention above.

[0044] The power device according to the embodiment of the present invention improves the overall performance of the power device and enhances the safety performance of the power device by setting the battery pack according to the second aspect embodiment above.

[0045] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 thus should not be construed as a limitation to the present utility model.

[0046] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, "a plurality" means two or more, unless otherwise specifically defined.

[0047] In the present utility model, unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or a communication connection; it may be directly connected, or indirectly connected through an intermediate medium, and may be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0048] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0049] Although the embodiments of the present utility model have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model, and the scope of the present utility model is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized in that: include: A housing, wherein the housing is formed with a receiving cavity and an opening communicating with the receiving cavity; An inner shell, the inner shell is arranged in the accommodating cavity, and a cavity is formed in the inner shell; The pole group is wound in the cavity, and the inner circumferential wall of the inner shell and the outer circumferential wall of the pole group are in contact with each other. A plurality of through holes arranged at intervals are formed on the circumferential wall of the inner shell, and each of the through holes penetrates the circumferential wall of the inner shell in the thickness direction of the circumferential wall of the inner shell.

2. The battery cell according to claim 1, characterized in that: The cross section of the inner peripheral wall of the inner shell is waist-shaped, and the cross section of the outer peripheral wall of the inner shell is rectangular.

3. The battery cell according to claim 2, characterized in that: The arc width W of the inner shell is at least 1 mm greater than the radius of the outermost arc of the pole group.

4. The battery cell according to claim 3, characterized in that: The length L of the inner shell is at least 5 mm smaller than the length of the outer shell, and / or the height of the inner shell is the same as the height of the accommodating cavity of the outer shell.

5. The battery cell according to claim 1, characterized in that: The diameter of the through hole is no greater than 5 mm.

6. The battery cell according to any one of claims 1 to 5, characterized in that: The thickness of the peripheral wall of the shell is in the range of 0.3 mm to 1 mm.

7. The battery cell according to any one of claims 1 to 5, characterized in that: The inner shell is formed as a high temperature resistant insulating material piece, and / or the outer shell is formed as an aluminum piece or a steel piece.

8. A battery pack, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 7.

9. A power device, characterized in that: A battery pack comprising the battery pack as claimed in claim 8.

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