Battery cell and battery pack

Abstract

The application provides a battery monomer and a battery pack. The battery monomer comprises a shell, a cover plate and an insulating piece. An inner wall of the shell is provided with a first wall surface, a step surface and a second wall surface. The cover plate is arranged in the shell and is welded with the first wall surface to form a welding part. The insulating piece is connected to one side of the cover plate along a first direction. A first gap is formed between the cover plate and the first wall surface. The welding part is located at one end of the first gap along the first direction. The size of the first gap along a second direction is smaller than the size of the step surface along the second direction. Therefore, the laser welding beam when the cover plate is welded with the first wall surface can pass through the first gap and irradiate on the step surface. The step surface is inclined in a direction away from the first gap. Along the inclined direction of the step surface, the extension line of the step surface intersects with the insulating piece. The insulating piece can block the light to prevent the reflected light from irradiating on the pole core in the accommodating cavity of the shell, so as to avoid the damage of the laser welding beam to the pole core.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a battery cell and battery pack. Background Technology

[0002] A battery cell includes a casing, a cover plate, and an electrode core. The electrode core is located inside the casing, and the cover plate seals the casing to protect the electrode core from external environmental influences. In existing technologies, the casing and cover plate are usually fixed by welding. However, during welding, the laser welding beam can easily penetrate the gap between the casing and the cover plate and irradiate the stepped surface inside the casing. This beam is then reflected back into the casing, causing the laser welding beam to irradiate the electrode core, resulting in damage and insulation failure, which seriously affects the performance of the battery cell. Utility Model Content

[0003] In view of this, this application provides a battery cell and a battery pack to at least solve the problem in the prior art that the laser welding beam may irradiate the electrode core during the welding of the casing and the cover plate, causing damage to the electrode core.

[0004] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0005] This application provides a battery cell having a first direction, a second direction, and a third direction that are perpendicular to each other. The battery cell includes: a casing, a cover plate, and an insulating component.

[0006] The inner wall of the housing is provided with a first wall surface, a stepped surface, and a second wall surface, wherein the first wall surface and the second wall surface are connected to both sides of the stepped surface along the first direction;

[0007] The cover plate is disposed inside the housing and is welded to the first wall to form a welded part; the insulating member is connected to the inner side of the cover plate along the first direction;

[0008] The cover plate has a first gap with the first wall surface, and the welded part is located at one end of the first gap along the first direction; and the dimension of the first gap along the second direction is smaller than the dimension of the step surface along the second direction.

[0009] The stepped surface is inclined in a direction away from the first gap, and the extension line of the stepped surface intersects the insulating member along the inclined direction of the stepped surface.

[0010] Secondly, this application provides a battery pack including any of the battery cells described above.

[0011] Compared with the prior art, the battery cell and battery pack described in this application have the following advantages:

[0012] The battery cell of this application includes: a housing, a cover plate, and an insulating component; the inner wall of the housing is provided with a first wall surface, a stepped surface, and a second wall surface, the first wall surface and the second wall surface being connected to both sides of the stepped surface along a first direction; the cover plate is disposed inside the housing and welded to the first wall surface to form a welded part; the insulating component is connected to the inner side of the cover plate along the first direction; there is a first gap between the cover plate and the first wall surface, and the welded part is located at one end of the first gap along the first direction; and the dimension of the first gap along the second direction is smaller than the dimension of the stepped surface along the second direction; thereby, the laser welding beam during the welding of the cover plate and the first wall surface can pass through the first gap and irradiate the stepped surface.

[0013] The stepped surface is inclined in a direction away from the first gap, and the extension line of the stepped surface intersects the insulating component along the inclined direction. When the laser welding beam irradiates the stepped surface, the laser welding beam will be reflected on the stepped surface. The area where the laser welding beam is reflected must be within the area formed by the multiple extension lines of the stepped surface and the first wall surface. Therefore, setting the extension lines of the stepped surface to intersect the insulating component means that the reflected light of the laser welding beam will necessarily fall on the insulating component. The insulating component can block the light to prevent the reflected light from irradiating the electrode core in the housing cavity, thereby avoiding damage to the electrode core by the laser welding beam, which is conducive to maintaining the good working performance of the electrode core and ensuring the performance of the battery cell.

[0014] The battery pack of this application has the same or similar advantages as the existing technology and the aforementioned battery cells, which will not be repeated here. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 A schematic diagram of a battery cell according to an embodiment of this application is shown;

[0017] Figure 2 An exploded view of the structure of a battery cell according to an embodiment of this application is shown;

[0018] Figure 3 A front view of a battery cell according to an embodiment of this application is shown;

[0019] Figure 4 It shows Figure 3 Enlarged schematic diagram of part I;

[0020] Figure 5 One of the simplified schematic diagrams of a stepped surface reflective welding beam is shown in one embodiment of this application;

[0021] Figure 6A second simplified schematic diagram of a stepped surface reflective welding beam is shown in an embodiment of this application;

[0022] Figure 7 A schematic diagram of a cover plate and a lower plastic sheet is shown in an embodiment of this application;

[0023] Figure 8 This illustration shows one of the schematic diagrams of removing the casing from a battery cell according to an embodiment of this application;

[0024] Figure 9 This is a second schematic diagram of a battery cell with its casing removed, as shown in an embodiment of this application.

[0025] Figure 10 A schematic diagram of the heat insulation plate portion of a battery cell is shown in an embodiment of this application.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1-Shell shell, 11-First wall surface, 12-Second wall surface, 13-Step surface,

[0028] 2-Cover plate, 21-Side panel, 22-Lower panel, 23-Chamfer,

[0029] 3-Insulating component, 301-Side surface, 31-Lower plastic, 32-Insulating layer, 321-First insulating part

[0030] 4-Welding section,

[0031] 51 - First gap, 52 - Second gap

[0032] 6-Insulation layer, 7-Electrode core, 8-Insulation board

[0033] Z - First direction, X - Second direction, Y - Third direction. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0036] The term "comprising" or any other variations thereof in the specification and claims of this application is intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0037] The following detailed description of a battery cell and battery pack provided in this application is illustrated with specific embodiments.

[0038] Firstly, embodiments of this application provide a single battery cell. Figure 1 A schematic diagram of a battery cell according to an embodiment of this application is shown. Figure 2 An exploded view of the structure of a battery cell according to an embodiment of this application is shown. Figure 3 This paper shows a front view of a battery cell according to an embodiment of the present application. Figure 4 It shows Figure 3 Enlarged schematic diagram of part I in the middle. Figure 5 and Figure 6 Simplified schematic diagrams of a stepped surface reflective welding beam are shown in the embodiments of this application.

[0039] Reference Figures 1 to 6As shown, the battery cell has two perpendicular directions: a first direction Z, a second direction X, and a third direction Y. The battery cell includes: a housing 1, a cover plate 2, and an insulating component 3. The inner wall of the housing 1 is provided with a first wall surface 11, a stepped surface 13, and a second wall surface 12. The first wall surface 11 and the second wall surface 12 are connected to the two sides of the stepped surface 13 along the first direction Z. The cover plate 2 is disposed inside the housing 1 and is welded to the first wall surface 11 to form a welded part 4. The insulating component 3 is connected to the inner side of the cover plate 2 along the first direction Z. There is a first gap 51 between the cover plate 2 and the first wall surface 11. The welded part 4 is located at one end of the first gap 51 along the first direction Z. The size of the first gap 51 along the second direction X is smaller than the size of the stepped surface 13 along the second direction X. The stepped surface 13 is inclined in a direction away from the first gap 51, and the extension line of the stepped surface 13 intersects the insulating component 3 along the inclined direction of the stepped surface 13.

[0040] Specifically, the first direction Z, the second direction X, and the third direction Y are mutually perpendicular. In this embodiment, "perpendicular" includes not only absolute perpendicularity but also generally considered approximately perpendicular, such as when the angle between any two directions Z, X, and Y is between 89° and 91°. These are all considered mutually perpendicular. Figure 1 As shown, the first direction Z can be regarded as the height direction of the battery cell, the second direction X can be regarded as the length direction of the battery cell, and the third direction Y can be regarded as the width direction of the battery cell.

[0041] like Figure 2 As shown, the housing 1 has a receiving cavity for placing the electrode core 7. The electrode core 7 is encapsulated within the receiving cavity, serving as the core for energy storage and conversion. A cover plate 2 is located at the opening of the receiving cavity and is fixedly connected to the housing 1 to seal the receiving cavity, protecting the electrode core 7 from external environmental interference and ensuring the charging and discharging performance of the battery cell. The cover plate 2 typically also has components such as terminals and explosion-proof valves. The terminals penetrate the cover plate and connect to the electrode core 7 to achieve energy output. The explosion-proof valve penetrates the cover plate 2, allowing gas generated during the operation of the electrode core 7 to be discharged.

[0042] like Figure 4 As shown, the housing 1 has an inner wall, which is the cavity wall of the receiving cavity. The inner wall of the housing 1 is provided with a first wall surface 11, a stepped surface 13, and a second wall surface 12. The first wall surface 11 and the second wall surface 12 are connected to both sides of the stepped surface 13 along the first direction Z. The first wall surface 11, the stepped surface 13, and the second wall surface 12 form a stepped structure. The first wall surface 11 and the second wall surface 12 can be arranged parallel to the first direction Z, and the stepped surface 13 intersects with the first direction Z.

[0043] The cover plate 2 is adapted to be installed at the opening end of the cavity of the housing 1. The edge of the cover plate 2 is fixedly connected to the end of the first wall surface 11 away from the step surface 13. The fixed connection is achieved by laser welding, thereby forming a welded part 4 at the end of the first wall surface 11. The welded part 4 forms a ring structure around the first direction Z on the first wall surface 11, thereby achieving a reliable connection between the cover plate 2 and the housing 1 and an effective seal of the cavity.

[0044] The insulating component 3 is connected to the inner side of the cover plate 2 along the first direction Z. The inner side of the cover plate 2 along the first direction Z refers to the bottom of the cover plate 2, that is, the side of the cover plate 2 closest to the receiving cavity. The insulating component 3 can be fixed to the inner side of the cover plate 2 by means of adhesive bonding, assembly bonding, snap-fit, etc. The shape of the insulating component 3 basically matches the shape of the cover plate 2. The size of the insulating component 3 is slightly smaller than the size of the cover plate 2. The insulating component 3 can completely cover the area where the electrode core 7 is located under the cover plate 2 to avoid electrical contact between the cover plate 2 and the electrode core 7, which could cause a short circuit in the battery cell.

[0045] like Figure 4 As shown, there is a first gap 51 between the cover plate 2 and the first wall surface 11, meaning that the cover plate 2 and the first wall surface 11 are spaced apart and do not contact each other. Since the cover plate 2 and the housing 1 are connected by laser welding, the welded part 4 formed by the welding is located at one end of the first gap 51 along the first direction Z. This first gap 51 allows the laser welding beam to pass through during welding, ensuring that the laser welding beam can accurately act on the connection between the cover plate 2 and the first wall surface 11, thereby ensuring the reliability of the welding. Moreover, the dimension of the first gap 51 along the second direction X is smaller than the dimension of the step surface 13 along the second direction X. That is, along the first direction Z, on a plane perpendicular to the first direction Z, the orthographic projection of the first gap 51 is located within the orthographic projection of the step surface 13. This means that the laser welding beam irradiated from the first direction Z will irradiate the step surface 13 completely.

[0046] like Figure 4 As shown, the step surface 13 is inclined in the direction away from the first gap 51, that is, the step surface 13 is an inclined surface, and the extension line of the step surface 13 intersects the insulating member 3 along the inclined direction. The extension line of the step surface 13 along its inclined direction is as follows: Figure 5As shown by the dashed line L1, multiple extension lines L1 form the extension surface of the step surface 13. It should be noted that when the laser welding beam irradiates the step surface 13, the laser welding beam will be reflected on the step surface 13. The area where the laser welding beam is reflected must be between the area formed by the extension surface of the step surface 13 and the first wall surface 11. Therefore, the intersection of the extension line of the step surface 13 with the insulating member 3 means that the extension surface of the step surface 13 intersects with the insulating member 3. This means that the reflected light from the laser welding beam must fall on the insulating member 3. The insulating member 3 can block the light to prevent the reflected light from irradiating the electrode core 7 in the housing cavity of the housing 1, thereby avoiding damage to the surface of the electrode core 7 by the laser welding beam, which is conducive to maintaining the good working performance of the electrode core 7, and thus ensuring the performance of the battery cell.

[0047] For example, Figure 5 An example is shown where a laser welding beam is incident on a stepped surface 13 and reflected, wherein the stepped surface 13 is an inclined surface, and the incident light of the laser welding beam is as follows: Figure 5 As shown in Figure a, light ray a shines from the first gap 51 onto the step surface 13, and is reflected on the step surface 13. The reflected outgoing light ray is as follows: Figure 5 As shown in b, light b shines on the surface of the insulating component 3.

[0048] Alternatively, in some embodiments of this application, such as Figure 6 As shown, Figure 6 An example is shown where a laser welding beam is irradiated onto a stepped surface 13 and reflected. The stepped surface 13 is an arc surface, with the center of curvature located near the cover plate 2 or the insulating member 3. The stepped surface 13 is inclined in a direction away from the first gap 51, such that the tangent of the stepped surface 13 intersects the insulating member 3 along the inclination direction. The tangent of the stepped surface 13 is shown as follows: Figure 6 As shown by the dashed line L2 in the diagram. It should be noted that... Figure 6 While only one tangent is shown, the stepped surface 13 also has multiple tangents, each of which intersects the insulating element 3. This means that the light reflected from the laser welding beam must fall onto the insulating element 3. For example, the incident light of the laser welding beam is as follows: Figure 6 As shown in Figure a, light ray a shines from the first gap 51 onto the step surface 13, and is reflected on the step surface 13. The reflected outgoing light ray is as follows: Figure 6 As shown in b, light b shines on the surface of the insulating component 3. The insulating component 3 can block the light to prevent the reflected light from shining on the electrode core 7 inside the housing 1, thereby avoiding damage to the surface of the electrode core 7 by the laser welding beam, which helps to maintain the good working performance of the electrode core 7 and thus ensures the performance of the battery cell.

[0049] In addition, the protection function of the laser welding beam can be achieved by optimizing the structure of the housing 1 and the position of the insulating component 3 in this embodiment of the application, without the need to add additional protective components. This is beneficial to simplify the production process of the battery cell, reduce production costs, and at the same time ensure the reliability of the welding between the cover plate 2 and the housing 1 and the sealing of the housing 1 cavity, thereby helping to ensure the stability of the electrochemical performance of the battery cell.

[0050] In some optional embodiments of this application, the battery cell further includes: a heat insulation layer 6; an insulating member 3 having a side surface 301, the side surface 301 being disposed opposite to the second wall surface 12; the heat insulation layer 6 being connected to the side surface 301, and the extension line of the step surface 13 intersecting the heat insulation layer 6 along the inclined direction of the step surface 13.

[0051] Specifically, taking a square battery cell as an example, both the casing 1 and the cover plate 2 have a square structure. The insulating component 3 can also be designed as a square structure to better insulate the cover plate 2 from the electrode core 7, preventing electrical contact between them. Therefore, the insulating component 3 has a side surface 301, such as... Figure 5 As shown, the side surface 301 is disposed opposite to the second wall surface 12 of the housing 1. That is, the side surface 301 is the surface on which the laser welding beam reflected by the stepped surface 13 is irradiated onto the insulating component 3.

[0052] The heat insulation layer 6 is connected to the side surface 301. The heat insulation layer 6 can be connected to the side surface 301 by adhesive bonding, interlocking, or by coating the side surface 301 with heat insulation material to form the heat insulation layer 6. The heat insulation layer 6 is made of materials with high temperature resistance, low thermal conductivity, and strong chemical stability, such as high-temperature resistant resin, ceramic fiber materials, and aerogel materials. The heat insulation layer 6 has good heat resistance and insulation properties, as well as resistance to laser penetration and electrolyte corrosion.

[0053] The heat insulation layer 6 is connected to the side surface 301, covering part or all of the surface of the side surface 301. In this embodiment, the heat insulation layer 6 can cover the irradiation area so that all the light reflected by the laser welding beam can irradiate the heat insulation layer 6. Along the inclined direction of the step surface 13, the extension line of the step surface 13 intersects with the heat insulation layer 6, which means that the light reflected by the laser welding beam will fall on the heat insulation layer 6. The heat insulation layer 6 can block the light and play a certain role in heat insulation, thereby helping to reduce the temperature rise of the side surface 301 of the insulating component 3, reduce the temperature inside the cavity of the housing 1, and thus help maintain the good working performance of the electrode core 7.

[0054] Refer to together Figures 7 to 9 As shown, Figure 7 A schematic diagram of a cover plate and a lower plastic part according to an embodiment of this application is shown. Figure 8 and Figure 9 Schematic diagrams of removing the casing from a single battery cell are shown in the embodiments of this application.

[0055] In some optional embodiments of this application, the insulating element 3 includes a lower plastic 31 and an insulating layer 32; the lower plastic 31 is connected to the cover plate 2, and the insulating layer 32 covers the surface of the lower plastic 31; the heat insulation layer 6 is connected to the side of the insulating layer 32 away from the lower plastic 31.

[0056] Specifically, such as Figure 2 and Figure 7 As shown, the lower plastic 31 is connected to the side of the cover plate 2 near the electrode core 7. The lower plastic 31 is usually made of rigid plastic material, such as polypropylene (PP), polycaprolactam (PA6), or polyimide (PI), and is fixedly connected to the cover plate 2 by means of snap-fit ​​or heat fusion. The lower plastic 31 is mainly used to achieve electrical isolation between the cover plate 2 and the electrode core 7 to avoid electrical contact between the two and cause short circuits in the battery cells. At the same time, the lower plastic 31 can strengthen the assembly stability of various functional components on the cover plate 2, such as the electrode posts, and improve their service life. It can also play a protective and buffering role between the cover plate 2 and the electrode core 7, further ensuring the structural integrity of the electrode core 7.

[0057] The insulating layer 32 covers the surface of the lower plastic 31. The insulating layer 32 is typically made of a high-temperature resistant insulating material, such as polyimide film. By covering the surface of the lower plastic 31, the insulating layer 32 eliminates potential insulation hazards caused by gaps or burrs in the lower plastic 31, thereby further ensuring electrical isolation between the cover plate 2 and the electrode core 7 and avoiding short-circuit risks. The insulating layer 32 can cover the entire surface of the lower plastic 31 or only a portion of it. For example, for areas with high insulation requirements, the insulating layer 32 can be covered on the surface of the lower plastic 31; for areas with relatively low insulation requirements, the surface of the lower plastic 31 can be optionally covered with the insulating layer 32.

[0058] In this embodiment, the side of the lower plastic 31 opposite to the second wall surface 12 is covered with an insulating layer 32, thereby connecting the heat insulation layer 6 to the side of the insulating layer 32 away from the lower plastic 31. The heat insulation layer 6 can be bonded to the insulating layer 32 with a high-temperature resistant adhesive, or a heat insulation material can be coated on the insulating layer 32 to form the heat insulation layer 6; the specific method is not limited in this embodiment. Using the structure of this embodiment, a double-layer protective structure including the insulating layer 32 and the heat insulation layer 6 can be formed on the surface of the lower plastic 31, further reducing the heat conducted to the lower plastic 31 and helping to delay the aging of the lower plastic 31 material.

[0059] in addition, Figure 8 In the schematic diagram of the battery cell with the casing removed, the insulating layer 32 covers the surface of the lower plastic 31, so that the heat insulation layer 6 is attached to the insulating layer 32. Figure 9In the schematic diagram of the battery cell with the casing removed, the insulating layer 32 does not cover the surface of the lower plastic 31, so the heat insulation layer 6 is attached to the lower plastic 31.

[0060] In some optional embodiments of this application, the insulating layer 32 includes a first insulating portion 321, which is disposed opposite to the second wall surface 12; a second gap 52 is provided between the first insulating portion 321 and the surface of the lower plastic 31.

[0061] Specifically, such as Figure 4 As shown, the first insulating part 321 is disposed opposite to the second wall surface 12. In conjunction with the aforementioned embodiment, since the side surface 301 of the insulating member 3 is disposed opposite to the second wall surface 12, when the insulating member 3 includes the lower plastic 31 and the insulating layer 32, and the insulating layer 32 covers the surface of the lower plastic 31, the first insulating part 321 can be regarded as the side surface 301 of the insulating member 3, so that the light reflected by the laser welding beam after being reflected by the stepped surface 13 will irradiate the first insulating part 321.

[0062] like Figure 4 As shown, a second gap 52 exists between the surface of the first insulating part 321 and the surface of the lower plastic 31. That is, the surfaces of the first insulating part 321 and the lower plastic 31 are spaced apart and do not contact each other. The second gap 52 is filled with a gas with low thermal conductivity, so that the existence of the second gap 52 can play a certain role in heat insulation, preventing heat from the first insulating part 321 from being directly conducted to the lower plastic 31. This helps to reduce the impact of the laser welding beam on the lower plastic 31, and also reduces the impact of the welding process between the cover plate 2 and the shell 1 on the electrode core 7.

[0063] In some optional embodiments of this application, the first insulating portion 321 has a double-layer structure, and the first insulating portion 321 is stacked along the second direction X.

[0064] Specifically, such as Figure 8 and Figure 9 As shown, the insulating layer 32 typically covers the entire outer periphery of the electrode core 7. During the production stage, the insulating layer 32 is a long strip structure. The width of the long strip structure is at least greater than the width of the electrode core 7, and the length of the long strip structure is at least greater than the unfolded length of the entire outer periphery of the electrode core 7. During the covering stage, the insulation layer 32 is covered along the outer periphery of the electrode core 7 starting from one end in the length direction as the beginning, and the insulation layer 32 is covered by covering the other end in the length direction as the end. The beginning and end coincide on the side of the electrode core 7 near the second wall surface 12, so that the insulating layer 32 forms a double-layer structure. The first insulating part 321 belongs to this part of the insulating layer 32, so the first insulating part 321 of the double-layer structure is stacked along the second direction X.

[0065] Since the light reflected by the stepped surface 13 will irradiate the first insulating part 321, the first insulating part 321 will bear more heat. Therefore, the first insulating part 321 is set as a double-layer structure, which can significantly enhance the insulation and heat insulation capacity of the first insulating part 321, further reduce the impact of the laser welding beam on the lower plastic 31, and reduce the impact of the welding process between the cover plate 2 and the shell 1 on the pole core 7.

[0066] In some optional embodiments of this application, the battery cell further includes: a core 7; the core 7 is disposed on the side of the lower plastic 31 away from the cover plate 2, and the insulating layer 32 also covers the surface of the core 7; a third gap exists between the core 7 and the lower plastic 31.

[0067] Specifically, such as Figure 2 As shown, the electrode core 7 is located on the side of the lower plastic 31 away from the cover plate 2, as... Figure 8 and Figure 9 As shown, the insulating layer 32 covers the entire outer circumferential surface of the electrode core 7. There is a third gap between the electrode core 7 and the lower plastic 31; that is, the electrode core 7 and the lower plastic 31 are spaced apart and do not contact each other. This arrangement prevents heat from the lower plastic 31 from being directly conducted to the electrode core 7, thereby further reducing the impact of the welding process between the cover plate 2 and the housing 1 on the electrode core 7.

[0068] Refer to together Figure 10 As shown, Figure 10 A schematic diagram of the heat insulation plate portion of a battery cell is shown in an embodiment of this application.

[0069] In some optional embodiments of this application, the battery cell further includes: a heat insulation plate 8; the heat insulation plate 8 is disposed on the side of the insulating member 3 near the second wall surface 12 and connected to the cover plate 2; along the inclined direction of the step surface 13, the extension line of the step surface 13 intersects with the heat insulation plate 8.

[0070] Specifically, the heat insulation board 8 can be made of materials with high temperature resistance, low thermal conductivity, and strong chemical stability, such as fiberglass board, ceramic fiber board, aerogel board, mica board, silicone board, etc. The heat insulation board 8 has good heat resistance and insulation properties, as well as properties such as not being easily penetrated by laser and resistance to electrolyte corrosion. Since the light reflected by the step surface 13 after the laser welding beam is reflected onto the insulating component 3 to form an irradiation area, in this embodiment, the heat insulation board 8 is placed on the side of the insulating component 3 near the second wall surface 12, and the heat insulation board 8 can be set to cover the irradiation area.

[0071] Along the inclined direction of the step surface 13, the extension line of the step surface 13 intersects with the heat insulation plate 8, which means that the light reflected by the laser welding beam will fall on the heat insulation plate 8. The heat insulation plate 8 can block the light and play a certain role in heat insulation, which helps to reduce the temperature rise of the insulating component 3, lower the temperature inside the housing 1 cavity, and thus help the electrode core 7 maintain good working performance.

[0072] Furthermore, the thickness of the insulation board 8 can be set according to actual needs. The thicker the insulation board 8, the better the heat insulation performance, but the weight is correspondingly heavier and the material cost is higher. The thinner the insulation board 8, the weaker the heat insulation performance, but the weight is correspondingly lighter and the material cost is lower. Therefore, the thickness of the insulation board 8 can be reasonably set by comprehensively considering factors such as heat insulation performance, lightweight requirements, and cost.

[0073] In some optional embodiments of this application, the roughness of the step surface 13 is greater than that of the first wall surface 11 or the second wall surface 12. Specifically, the step surface 13 may be provided with concave-convex structures, embossed structures, textured structures, etc. to form a rough surface. The rough surface is beneficial to convert the directional reflection of the laser welding beam into diffuse reflection, thereby dispersing the reflected light and avoiding local strong light. This also avoids the situation where the insulating component 3 is excessively ablated in some areas, further reducing the impact of the welding process between the cover plate 2 and the shell 1 on the insulating component 3 and the electrode core 7.

[0074] In some optional embodiments of this application, reference is made to Figure 4 As shown, the cover plate 2 includes a side plate surface 21 and a lower plate surface 22. The side plate surface 21 is the surface close to the inner wall of the housing 1, and a first gap 51 is formed between the side plate surface 21 and the first wall surface 11. The lower plate surface 22 is perpendicular to the side plate surface 21 and is the surface close to the electrode core 7. The insulating member 3 is connected to the lower plate surface 22. A chamfer 23 is provided at the transition connection between the side plate surface 21 and the lower plate surface 22. Compared with a right angle structure, the chamfer 23 can block the welding beam reflected by the step surface 13 to a certain extent, thereby reducing the area of ​​the laser welding beam irradiating onto the insulating member 3 and further improving the impact on the electrode core 7.

[0075] Secondly, embodiments of this application provide a battery pack, including the battery cells of any of the foregoing embodiments. Specifically, the battery pack also includes a housing, electrical connection components, etc., with multiple battery cells disposed inside the housing. The multiple battery cells are connected in series or in parallel to form a battery pack, and the battery pack is electrically connected to an external circuit through the electrical connection components, thereby realizing the charging and discharging of the battery pack.

[0076] Among them, the battery cell adopts the battery cell of any of the aforementioned embodiments. During the welding process between the cover plate and the shell, the laser welding beam can avoid damage to the electrode core, which is conducive to maintaining the good working performance of the electrode core, thereby ensuring the performance of the battery cell and thus ensuring the performance of the battery pack.

[0077] It should be understood that the phrase "some embodiments" throughout the specification means that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, "some embodiments" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.

[0078] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery cell having three perpendicular directions (Z, X, and Y), characterized in that, The battery cell includes: a casing (1), a cover plate (2), and an insulating component (3); The inner wall of the housing (1) is provided with a first wall surface (11), a stepped surface (13) and a second wall surface (12), and the first wall surface (11) and the second wall surface (12) are connected to both sides of the stepped surface (13) along the first direction (Z); The cover plate (2) is disposed inside the housing (1) and welded to the first wall surface (11) to form a welded part (4); the insulating member (3) is connected to the inner side of the cover plate (2) along the first direction (Z); The cover plate (2) has a first gap (51) with the first wall surface (11), and the welded part (4) is located at one end of the first gap (51) along the first direction (Z); and the size of the first gap (51) along the second direction (X) is smaller than the size of the step surface (13) along the second direction (X); The stepped surface (13) is inclined in a direction away from the first gap (51), and the extension line of the stepped surface (13) intersects the insulating member (3) along the inclined direction of the stepped surface (13).

2. The battery cell according to claim 1, characterized in that, The battery cell further includes: a heat insulation layer (6); The insulating member (3) has a side surface (301) which is disposed opposite to the second wall surface (12); The heat insulation layer (6) is connected to the side surface (301), and the extension line of the step surface (13) intersects the heat insulation layer (6) along the inclined direction of the step surface (13).

3. The battery cell according to claim 2, characterized in that, The insulating component (3) includes a lower plastic (31) and an insulating layer (32); The lower plastic (31) is connected to the cover plate (2), and the insulating layer (32) covers the surface of the lower plastic (31); The heat insulation layer (6) is connected to the side of the insulating layer (32) away from the lower plastic (31).

4. The battery cell according to claim 3, characterized in that, The insulating layer (32) includes a first insulating portion (321), which is disposed opposite to the second wall surface (12); There is a second gap (52) between the first insulating part (321) and the surface of the lower plastic (31).

5. The battery cell according to claim 4, characterized in that, The first insulating part (321) has a double-layer structure, and the first insulating part (321) is stacked along the second direction (X).

6. The battery cell according to claim 3, characterized in that, The battery cell also includes: an electrode core (7); The electrode core (7) is located on the side of the lower plastic (31) away from the cover plate (2), and the insulating layer (32) also covers the surface of the electrode core (7); There is a third gap between the pole core (7) and the lower plastic (31).

7. The battery cell according to claim 1, characterized in that, The battery cell also includes: a heat insulation plate (8); The heat insulation plate (8) is disposed on the side of the insulating member (3) near the second wall surface (12) and is connected to the cover plate (2); Along the inclination direction of the stepped surface (13), the extension line of the stepped surface (13) intersects with the heat insulation plate (8).

8. The battery cell according to claim 1, characterized in that, The roughness of the stepped surface (13) is greater than that of the first wall surface (11) or the second wall surface (12).

9. The battery cell according to claim 1, characterized in that, The cover plate (2) includes a side plate surface (21) and a lower plate surface (22). The side plate surface (21) forms the first gap (51) with the first wall surface (11). The lower plate surface (22) is perpendicular to the side plate surface (21). The insulating component (3) is connected to the lower plate surface (22); the transition connection between the side plate surface (21) and the lower plate surface (22) is provided with a chamfer (23).

10. A battery pack, characterized in that, Includes the battery cell described in any one of claims 1 to 9.

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