Battery casing, power battery and battery pack

Abstract

This utility model relates to the field of power battery technology, and provides a battery casing, a power battery, and a battery pack. The battery casing includes: a shell, an explosion-proof valve, and at least one top cover; the shell has at least one opening and at least four end faces; the top cover is correspondingly fitted onto the opening; the outer edge of the explosion-proof valve has a connection area; the connection area is welded to the end face with a non-maximum area; the thickness of the shell is W, and the thickness of the connection area is W1, where W and W1 satisfy 0.4≤W1 / W≤1; the extension direction of the shell thickness is perpendicular to the end face; the explosion-proof valve has a closed state and an open state; the explosion-proof valve, the top cover, and the shell together form a sealed battery casing when in the closed state; the explosion-proof valve in the open state connects the inner and outer spaces of the battery casing. This battery casing is used to improve the safety and sealing reliability of the battery under abnormal operating conditions.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, and in particular to a battery casing, a power battery, and a battery pack. Background Technology

[0002] In related technologies, the explosion-proof valve of a power battery is mostly located on the top cover. When the battery encounters abuse conditions such as overcharging, over-discharging, short circuits, or mechanical damage, the internal pressure will rise rapidly. Once the pressure reaches the opening pressure of the explosion-proof valve, it will open to release pressure, thereby reducing the risk of battery fire or explosion. However, in this layout, the terminals are also located on the top cover. Therefore, once the explosion-proof valve opens, the high-temperature gas and liquid discharged from the battery will directly impact the high and low voltage wiring harnesses and insulation layer on the top cover, easily causing short circuits and high-voltage arcing, further increasing the risk of battery pack fire or even explosion. In addition, existing designs have improperly handled explosion-proof valve weld heights, resulting in bulges on the battery sides. This not only affects the structural stability of the power battery but may also cause leakage in unexpected locations, increasing safety hazards during battery use. Therefore, it is urgent to improve these issues. Utility Model Content

[0003] This utility model provides a battery casing, a power battery, and a battery pack. The battery casing is used to improve the safety and sealing reliability of the battery under abnormal operating conditions.

[0004] According to a first aspect of the present invention, a battery casing is provided, comprising: a housing, an explosion-proof valve, and at least one top cover; the housing has at least one opening and at least four end faces; the top cover is correspondingly fitted onto the opening; the outer edge of the explosion-proof valve has a connecting area; the connecting area is welded to the end face with a non-maximum area; the thickness of the housing is W, and the thickness of the connecting area is W1, wherein W and W1 satisfy 0.4≤W1 / W≤1; the extension direction of the thickness of the housing is perpendicular to the end face; the explosion-proof valve has a closed state and an open state; the explosion-proof valve, the top cover, and the housing in the closed state together form a sealed battery casing; the explosion-proof valve in the open state connects the inner and outer spaces of the battery casing.

[0005] Optionally, when the number of end faces is 4, the connecting area is welded to the two end faces with the smallest area; when the number of end faces is 5, the connecting area is welded to the end face with a non-largest area; W and W1 satisfy: 0.3mm≤W≤0.8mm, 0.2mm≤W1≤0.5mm, 0.4≤W1 / W≤0.8.

[0006] Optionally, when the number of the end faces is 4, the connection area is welded to two end faces with the smallest area among them; when the number of the end faces is 5, the connection area is welded to an end face with a non-maximum area; W and W1 satisfy: 0.1 mm ≤ W1 = W ≤ 1 mm.

[0007] Optionally, the explosion-proof valve further has a scoring area with an opening facing outside the battery case; the contour of the scoring area is located within the contour of the connection area; the thickness of the scoring area is W2, and W2 and W1 satisfy: W2 < W1; when the scoring area is damaged, the explosion-proof valve is in an open state; when the scoring area remains intact, the explosion-proof valve is in a closed state.

[0008] Optionally, the explosion-proof valve further has a buffer area; the buffer area is located between the scoring area and the connection area; the thickness of the buffer area is W3, and W1, W2 and W3 satisfy: W2 < W3 < W1.

[0009] Optionally, an opening area is provided in the scoring area; the thickness of the opening area is W4, and W4 and W2 satisfy W4 > W2.

[0010] Optionally, the number of the top covers is 1, the housing is in a cuboid shape, and its six faces are set as parallel first end faces and second end faces, parallel third end faces and fourth end faces, a fifth end face and an opening opposite to the fifth end face, and the areas of each end face satisfy: S1 ≥ S2 ≥ S3; wherein, the areas of the first end face and the second end face are both S1, the areas of the third end face and the fourth end face are both S2, and the areas of the fifth end face and the opening are both S3; the explosion-proof valve is located on at least one of the third end face, the fourth end face and the fifth end face.

[0011] Optionally, the number of the top covers is 2, the housing is in a cuboid shape, and its six faces are set as parallel first end faces and second end faces, parallel third end faces and fourth end faces, opposite first opening and second opening, and the two top covers are respectively and correspondingly covered on the first opening and the second opening, and the areas of each end face satisfy: S1 ≥ S2; wherein, the areas of the first end face and the second end face are both S1, and the areas of the third end face and the fourth end face are both S2; the explosion-proof valve is located on at least one of the third end face and the fourth end face.

[0012] According to the second aspect of the embodiments of the present invention, a power battery is provided, including: a pole core, an electrolyte and the battery case according to any one of the first aspect; the pole core and the electrolyte are both located inside the battery case; the pole core is electrically connected to a pole column in the top cover; the pole column penetrates through the top cover; when the pressure exerted by the electrolyte or the gas generated by it on the housing is higher than a preset pressure value, the explosion-proof valve enters an open state from a closed state. ]

[0013] According to a third aspect of the present invention, a battery pack is provided, the battery pack including a plurality of battery casings according to any one of the first aspects; the plurality of battery casings are fixed in a pairwise adjacent manner, wherein the end face with the largest area of ​​each battery casing is directly opposite the end face with the largest area of ​​the other adjacent battery casings.

[0014] Compared with existing technologies, the advantages of this invention are as follows: By setting the ratio range between the thickness of the shell and the thickness of the connecting area, the connection strength between the explosion-proof valve and the shell is ensured to be sufficiently high. It also ensures that after the explosion-proof valve is fixed to the shell using welding, the height of the weld point will not cause bulges on the side of the battery, and ensures that the seal is broken through the explosion-proof valve when the pressure inside the battery shell is too high. Placing the explosion-proof valve on the smaller end face avoids direct impact of high-temperature gas and liquid on the electrical components on the top cover, reducing the risk of fire caused by short circuits. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural schematic diagram of a battery casing according to an exemplary embodiment.

[0016] Figure 2 This is a partial cross-sectional view of a battery casing with solder joints located on the outside, according to an exemplary embodiment.

[0017] Figure 3 This is a partial cross-sectional view of a battery casing with solder joints located on the inside, according to another exemplary embodiment.

[0018] Figure 4 This is a cross-sectional structural schematic diagram of a power battery according to an exemplary embodiment.

[0019] Figure 5 This is a schematic diagram of a battery pack structure according to an exemplary embodiment.

[0020] Explanation of the reference numerals in the figure:

[0021] 11. Housing; 12. Explosion-proof valve; 13. Electrode core; 14. Protective plate; 15. Accommodation space; 16. Welding point. Detailed Implementation

[0022] Unless otherwise defined, the technical or scientific terms used in this specification shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. Specific embodiments of this invention will be described below with reference to the accompanying drawings. It should be noted that, in order to provide a concise description, this specification cannot provide a detailed description of all features of the actual embodiments. Without departing from the spirit and scope of this invention, those skilled in the art can make modifications and substitutions to the embodiments of this invention, and the resulting embodiments are also within the protection scope of this invention.

[0023] like Figure 1 As shown, the first embodiment of this utility model provides a battery casing, including: a casing 11, an explosion-proof valve 12, and at least one top cover; the casing 11 has at least one opening and at least four end faces; the top cover is correspondingly fitted onto the opening; the outer edge of the explosion-proof valve 12 has a connecting area; the connecting area is welded to the end face with a non-maximum area; the thickness of the casing 11 is W, the thickness of the connecting area is W1, and W and W1 satisfy 0.4≤W1 / W≤1; the extension direction of the thickness of the casing is perpendicular to the end face; the explosion-proof valve 12 has a closed state and an open state; the explosion-proof valve 12 in the closed state, the top cover, and the casing 11 together form a sealed battery casing; the explosion-proof valve 12 in the open state connects the inner and outer spaces of the battery casing.

[0024] In some specific embodiments, the top cover is provided with a pole post, which is used to electrically connect to the electrode core 13.

[0025] In other specific embodiments, both the housing 11 and the explosion-proof valve 12 are made of aluminum alloy plate or stainless steel plate.

[0026] In some specific embodiments, the thickness extends along the Z-direction, and the end face of the explosion-proof valve 12 extends along the plane containing the Y and X directions. The Z, Y, and X directions are perpendicular to each other.

[0027] It is worth noting that this embodiment ensures a sufficiently high connection strength between the explosion-proof valve 12 and the housing 11 by setting the ratio range between the thickness of the housing 11 and the thickness of the connecting area. It also ensures that after the explosion-proof valve 12 is fixed to the housing 11 using welding, the height of the weld point 16 will not cause a bulge on the side of the battery, and that the seal will be breached by the explosion-proof valve 12 when the pressure inside the battery housing is too high. Placing the explosion-proof valve 12 on a smaller end face avoids direct impact of high-temperature gas and liquid on the electrical components on the top cover, reducing the risk of fire caused by short circuits.

[0028] In some embodiments, when the number of end faces is 4, the connecting area is welded to the two end faces with the smallest area; when the number of end faces is 5, the connecting area is welded to the end face with a non-largest area; W and W1 satisfy: 0.3mm≤W≤0.8mm, 0.2mm≤W1≤0.5mm, 0.4≤W1 / W≤0.8.

[0029] In some specific embodiments, W=0.3mm and W1=0.2mm.

[0030] In other specific embodiments, W=0.8mm and W1=0.5mm.

[0031] In some specific embodiments, W=0.55mm and W1=0.35mm.

[0032] In some specific embodiments, at least one side of the connection area is provided with a receiving space 15, the total thickness of the receiving space 15 is W-W1, and the receiving space 15 is used to accommodate the weld point 16 between the explosion-proof valve 12 and the end face.

[0033] It is worth noting that this embodiment ensures the connection strength between the explosion-proof valve 12 and the housing 11 by limiting the relationship between the thickness W1 of the connection area and the thickness W of the housing 11. Simultaneously, it prevents the force exerted on the housing 11 by the expansion of the electrode core 13 or electrolyte during battery use from causing excessive strain on the explosion-proof valve 12, thus ensuring the reliability and service life of the explosion-proof valve 12. Furthermore, for the structure where the housing 11 and the explosion-proof valve 12 are welded, a space 15 is required to accommodate the weld height; therefore, W > W1, ensuring that there are no weld protrusions on the end face of the battery casing after the explosion-proof valve 12 is welded.

[0034] like Figure 2 In some of the examples shown, the battery casing is assembled first and then welded, and the accommodating space 15 and the weld point 16 are both located on the outside of the battery casing.

[0035] like Figure 3 In some of the examples shown, the battery casing is assembled by welding and then bending, so that the accommodating space 15 and the welding point 16 are both located on the inside of the battery casing.

[0036] It is worth noting that the thickness of the solder joint 16 is less than the thickness of the accommodating space 15.

[0037] In some embodiments, when the number of end faces is 4, the connecting area is welded to the two end faces with the smallest area; when the number of end faces is 5, the connecting area is welded to the end face with a non-largest area; W and W1 satisfy: 0.1mm≤W1=W≤1mm.

[0038] In some specific embodiments, W1 = 0.1 mm.

[0039] In some other specific embodiments, W1 = 1 mm.

[0040] In some further specific embodiments, W1 = 0.55 mm.

[0041] It should be noted that the explosion-proof valve 12 is integrally provided with the end face with the smallest area and adopts an integral stamping production process.

[0042] In some embodiments, the explosion-proof valve 12 further has a scoring area with an opening facing outside the battery case; the contour of the scoring area is located inside the contour of the connection area; the thickness of the scoring area is W2, and W2 and W1 satisfy: W2 < W1; when the scoring area is damaged, the explosion-proof valve 12 is in an open state; when the scoring area remains intact, the explosion-proof valve 12 is in a closed state.

[0043] In some specific embodiments, W2 ≤ 0.2 mm. In some examples, W2 = 0.2 mm. In some other examples, W2 = 0.1 mm. In some further examples, W2 = 0.05 mm.

[0044] It should be noted that the scoring area remains intact after the battery case is assembled. When the pressure difference inside and outside the battery case is too high, the scoring area is damaged. The scoring area is the weakest area of the explosion-proof valve 12, and the explosion-proof valve 12 relieves pressure through the damage of the scoring area.

[0045] In some embodiments, the explosion-proof valve 12 further has a buffer area; the buffer area is located between the scoring area and the connection area; the thickness of the buffer area is W3, and W1, W2 and W3 satisfy: W2 < W3 < W1.

[0046] In some specific embodiments, 0.1 mm ≤ W3 ≤ 0.2 mm. In some examples, W3 = 0.2 mm. In some other examples, W3 = 0.1 mm. In some further examples, W3 = 0.15 mm.

[0047] It should be noted that the buffer area is the area where the welding area and the scoring area transition, which is used to disperse stress, avoid stress directly concentrating on the welding area, thereby reducing the risk of welding point failure. The buffer area can provide additional support before the explosion-proof valve 12 is opened, ensuring that even in a high-pressure environment, the welding structure can remain intact and prevent unexpected leakage or structural damage.

[0048] In some embodiments, an opening area is provided in the scoring area; the thickness of the opening area is W4, and W4 and W2 satisfy W4 > W2.

[0049] In some specific embodiments, W4 ≥ 0.2 mm. In some examples, W4 = 0.2 mm. In other examples, W4 = 0.5 mm. In still other examples, W4 = 0.35 mm.

[0050] It is worth noting that by setting the thickness W4 of the opening area to be greater than the thickness W2 of other parts of the scored area, it is ensured that the explosion-proof valve 12 can accurately rupture and open in the preset opening area when the internal pressure of the battery reaches a certain threshold. This improves the reliability and accuracy of the explosion-proof valve 12 in responding to changes in internal pressure, avoiding safety hazards caused by premature or delayed opening. Although the opening area is designed to be a relatively thick part, it is still located within the scored area, ensuring good sealing under normal operating conditions. At the same time, it can effectively release pressure in extreme situations. This design ensures both the stability and safety of the battery in daily use and provides necessary safety protection in emergencies. The thicker opening area helps guide high-pressure gas and liquid to release along a predetermined path, reducing the impact on surrounding structures, especially protecting electrical components from direct damage. This design helps reduce the risk of short circuits caused by high-temperature gas and liquid eruptions, further improving the overall safety of the battery.

[0051] In some embodiments, the number of top covers is 1, the housing is a cuboid with 6 faces, 11, having 1 opening and 5 end faces; the 5 end faces include a first end face and a second end face that are parallel to each other, a third end face and a fourth end face that are parallel to each other, a fifth end face and an opening opposite to the fifth end face, and the area of ​​each end face satisfies: S1≥S2≥S3; wherein, the area of ​​the first end face and the second end face is S1, the area of ​​the third end face and the fourth end face is S2, and the area of ​​the fifth end face and the opening is S3; the explosion-proof valve 12 is located on at least one of the third end face, the fourth end face and the fifth end face.

[0052] In some specific embodiments, the number of explosion-proof valves 12 is one. In some examples, a single explosion-proof valve 12 is located on the third end face. In other examples, a single explosion-proof valve 12 is located on the fourth end face. In still other examples, a single explosion-proof valve 12 is located on the fifth end face.

[0053] In other specific embodiments, the number of explosion-proof valves 12 is two. In some examples, the two explosion-proof valves 12 are located on the third end face and the fourth end face, respectively. In other examples, both explosion-proof valves 12 are located on the third end face. In still other examples, both explosion-proof valves 12 are located on the fourth end face. In yet another example, both explosion-proof valves 12 are located on the fifth end face.

[0054] It is worth noting that by placing the explosion-proof valve 12 on the smaller first or second end face, high-temperature gas and liquid can be effectively prevented from directly impacting the electrical components on the top cover, reducing the risk of fire caused by short circuits. Even when the internal pressure of the battery abnormally increases, it ensures that the safe discharge path is away from the top cover, preventing the terminals on the top cover from contacting the high-temperature gas or liquid discharged by the explosion-proof valve 12, ensuring that high-voltage arcing and short circuits do not occur, and reducing the risk of battery fire or explosion.

[0055] In some embodiments, the number of top covers is two, and the housing is a cuboid with six faces arranged as 11, having two openings and four end faces. The four end faces include a first end face and a second end face that are parallel to each other, a third end face and a fourth end face that are parallel to each other, and a first opening and a second opening that are opposite to each other. The two top covers are fitted onto the first opening and the second opening in a one-to-one correspondence, and the area of ​​each end face satisfies: S1 ≥ S2; wherein the area of ​​the first end face and the second end face is both S1, and the area of ​​the third end face and the fourth end face is both S2; the explosion-proof valve 12 is located on at least one of the third end face and the fourth end face. In some examples, the first end face is perpendicular to the third end face, the second end face is perpendicular to the fourth end face, and the first end face, the second end face, the third end face, and the fourth end face are connected end to end.

[0056] In some specific embodiments, the two top covers are configured as a positive electrode top cover and a negative electrode top cover. The positive electrode top cover and the negative electrode top cover are arranged parallel to each other at opposite ends of the housing 11. The first end face, the third end face, the second end face, and the fourth end face are connected end to end. The first end face, the third end face, the second end face, and the fourth end face are all connected to the positive electrode top cover, and the first end face, the third end face, the second end face, and the fourth end face are all connected to the negative electrode top cover.

[0057] In this embodiment, the explosion-proof valve 12 is placed on the first or second end face, which has a smaller area. This effectively prevents high-temperature gas and liquid from directly impacting electrical components on the top cover, such as the positive and negative electrode top covers and their connectors, during the depressurization process. This design significantly reduces the risk of short circuits, arcing, or even fires caused by the high-temperature gas and liquid ejected when the explosion-proof valve 12 is opened, thereby improving the safety performance of the power battery under abnormal operating conditions.

[0058] In some embodiments, the battery housing further includes a protective plate 14. The protective plate 14 is located outside the explosion-proof valve 12. At least one of the housing 11 and the explosion-proof valve 12 is detachably connected to the protective plate 14. When the explosion-proof valve 12 is closed, the protective plate 14 remains connected to at least one of the housing 11 and the explosion-proof valve 12. When the explosion-proof valve 12 is open, the protective plate 14 is detached from the battery housing.

[0059] In some specific embodiments, the length of the protective plate 14 is L, and the length of the explosion-proof valve 12 is L1, where L1 ≤ L. The extension direction of the length is the X direction. The protective plate 14 covers the outside of the explosion-proof valve 12 to prevent the explosion-proof valve 12 from entering the open state due to external force.

[0060] In other specific embodiments, the protective sheet 14 is attached to the end face of the battery casing.

[0061] In some other specific embodiments, the protective sheet 14 is bonded to the connection area.

[0062] It is worth noting that the adhesive connection is achieved using an adhesive or bonding layer, and the bonding strength is less than the pressure difference between the inside and outside of the battery casing when the scored area is damaged.

[0063] like Figure 4 As shown, according to the second embodiment of the present invention, a power battery is provided, comprising: an electrode core 13, an electrolyte, and a battery casing as described in any of the above embodiments; the electrode core 13 and the electrolyte are both located inside the battery casing; the electrode core 13 is electrically connected to a terminal post in the top cover; the terminal post penetrates the top cover; when the pressure exerted on the casing 11 by the electrolyte or the gas it generates is higher than a preset pressure value, the explosion-proof valve 12 changes from a closed state to an open state.

[0064] In some specific embodiments, the electrode post includes a positive electrode post and a negative electrode post, with the positive electrode top cover connected to the positive electrode post and the negative electrode top cover connected to the negative electrode post.

[0065] In other specific embodiments, the electrode core 13 is immersed in the electrolyte. In some examples, the electrode core 13 includes an insulating layer, a positive electrode, and a negative electrode. The insulating layer is located between the positive electrode and the negative electrode, and the insulating layer is an insulator to prevent direct contact between the positive electrode and the negative electrode, which could lead to a short circuit.

[0066] In some specific embodiments, the positive electrode plate is electrically connected to the positive electrode post. The negative electrode plate is electrically connected to the negative electrode post.

[0067] In some specific embodiments, the pole is connected to a cable, and the cable has an insulation layer on its outer side. The end face with the largest area is coated with an insulating protective layer. The cable insulation layer contacts the end face with the largest area.

[0068] In some examples, the cable is configured as a high- and low-voltage harness to transmit different voltages.

[0069] This embodiment applies an insulating protective layer to the end face with the largest area and sets a cable insulation layer on the outside of the cable to ensure good insulation performance of the electrical connection parts and reduce the risk of short circuits. Especially in the application scenario of high-voltage wiring harnesses, this design can improve the safety of the power battery.

[0070] like Figure 5 As shown, according to a third embodiment of the present invention, a battery pack is provided, the battery pack including a plurality of battery cases as described in any of the above embodiments; the plurality of battery cases are fixed in a pairwise adjacent manner, wherein the end face with the largest area of ​​each battery case is directly opposite the end face with the largest area of ​​the other adjacent battery case.

[0071] In some specific embodiments, the stacking direction of two adjacent battery casings is along the Y direction.

[0072] In other specific embodiments, the plurality of battery housings includes a first battery housing and a second battery housing. A first end face of the first battery housing is adjacent to a second end face of the second battery housing.

[0073] It is worth noting that when the battery casings are stacked, the largest end face of each battery casing faces the largest end face of the adjacent battery casing. This layout makes full use of the spatial characteristics of the end faces, making the entire battery pack structure more compact. Especially in the design of battery modules or battery packs, this arrangement helps to improve the overall energy density and space utilization, and reduce redundant space waste. Since the largest end face is usually used to arrange the insulation layer and cables, aligning its adjacent end faces facilitates the design of a unified thermal management scheme and can improve heat dissipation efficiency. At the same time, this layout also facilitates the implementation of a modular thermal management system, ensuring uniform temperature distribution among the battery casings and avoiding safety risks caused by localized overheating.

[0074] In this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0075] The above description of the embodiments is intended to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without creative effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope and spirit of the present invention are within the scope of the present invention.

Claims

1. A battery casing, characterized in that, include: Housing, explosion-proof valve, and at least one top cover; The housing has at least one opening and at least four end faces; The top cover fits onto the opening in a corresponding manner; The outer edge of the explosion-proof valve has a connection area; the connection area is welded to the end face that is not the largest area. The thickness of the shell is W, and the thickness of the connecting area is W1, where W and W1 satisfy 0.4≤W1 / W≤1; the extension direction of the thickness of the shell is perpendicular to the end face. The explosion-proof valve has a closed state and an open state; The explosion-proof valve, the top cover, and the housing, when in a closed state, together form a sealed battery casing; The explosion-proof valve, when in the open state, connects the inner and outer spaces of the battery casing.

2. The battery case according to claim 1, wherein When the number of end faces is 4, the connecting area is welded to the two end faces with the smallest area; when the number of end faces is 5, the connecting area is welded to the end face with a non-largest area; W and W1 satisfy: 0.3mm≤W≤0.8mm, 0.2mm≤W1≤0.5mm, 0.4≤W1 / W≤0.

8.

3. The battery case of claim 1, wherein When the number of end faces is 4, the connection area is welded to the two end faces with the smallest area; when the number of end faces is 5, the connection area is welded to the end face with a non-largest area; W and W1 satisfy: 0.1mm≤W1=W≤1mm.

4. The battery case of claim 1, wherein The explosion-proof valve also has a serrated area with an opening facing outwards from the battery casing; the outline of the serrated area is located within the outline of the connection area; The thickness of the indented region is W2, and W2 satisfies W1: W2 <W1; When the scored area is damaged, the explosion-proof valve is in the open state; when the scored area remains intact, the explosion-proof valve is in the closed state.

5. The battery case of claim 4, wherein, The explosion-proof valve also has a buffer area; the buffer area is located between the scored area and the connecting area; the thickness of the buffer area is W3, and W1, W2 and W3 satisfy: W2 <W3<W1。 6. The battery case of claim 4, wherein An opening area is provided within the grooved area; The thickness of the opening area is W4, and W4 and W2 satisfy W4>W2.

7. The battery case of claim 1, wherein The number of top covers is 1. The shell is a cuboid with 6 faces: a first end face and a second end face that are parallel to each other; a third end face and a fourth end face that are parallel to each other; a fifth end face; and an opening opposite the fifth end face. The area of ​​each end face satisfies the following: S1≥S2≥S3; Wherein, the area of ​​the first end face and the second end face is S1, the area of ​​the third end face and the fourth end face is S2, and the area of ​​the fifth end face and the opening is S3. The explosion-proof valve is located on at least one of the third, fourth, and fifth end faces.

8. The battery case of claim 1, wherein, The number of top covers is two. The shell is a cuboid with six faces: a first and a second parallel end face, a third and a fourth parallel end face, and a first and a second opening opposite each other. The two top covers are fitted onto the first and second openings in a one-to-one correspondence. The area of ​​each end face satisfies the following condition: S1≥S2; The area of ​​the first end face and the second end face is S1, and the area of ​​the third end face and the fourth end face is S2. The explosion-proof valve is located on at least one of the third and fourth end faces.

9. A power cell, characterized by include: Electrode core, electrolyte, and battery casing as described in any one of claims 1 to 8; The electrode core and electrolyte are both located inside the battery casing; the electrode core is electrically connected to the terminal post in the top cover; the terminal post penetrates the top cover; When the pressure exerted on the shell by the electrolyte or the gas it generates is higher than a preset pressure value, the explosion-proof valve changes from a closed state to an open state.

10. A battery pack characterized by comprising: The battery pack includes a plurality of battery casings as described in any one of claims 1 to 8; Several of the battery casings are fixed in pairs adjacent to each other, wherein the end face with the largest area of ​​each battery casing is directly opposite the end face with the largest area of ​​the other adjacent battery casings.

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