Battery shell assembly and secondary battery

Abstract

The utility model provides a battery shell assembly and a secondary battery, the battery shell assembly comprises a battery shell and an anti-explosion sheet, and the battery shell and the anti-explosion sheet are both made of steel; the two ends of the battery shell in the length direction are connected with the battery cover plate; the battery shell is provided with two first side walls which are arranged at intervals in the width direction of the battery shell, one of the first side walls is provided with a plurality of anti-explosion holes which are formed at intervals in the length direction of the battery shell, and at least two anti-explosion holes are formed in the two sides of the first side walls in the length direction of the battery shell respectively; and the explosion-proof sheets are fixed on the battery shell and cover the corresponding explosion-proof holes. The two sides of the first side wall in the length direction of the battery shell are respectively provided with one explosion-proof hole, so that the distance between the positive electrode and the negative electrode of the battery cell and the explosion-proof holes in the corresponding sides can be shortened, gas and / or a solid-liquid mixture sprayed from the positive electrode and the negative electrode of the battery cell can be discharged from the explosion-proof holes in the corresponding sides, the time consumed for discharging is shortened, and the production efficiency is improved. And battery explosion or leakage is effectively prevented.

Description

Technical Field

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

[0002] For safety reasons, during the manufacturing process of secondary batteries (such as lithium-ion batteries), explosion-proof valves are installed on the battery cover or battery casing. The explosion-proof valve contains an explosion-proof disc with grooves. The grooves are the weakest points of the explosion-proof disc. When the internal pressure of the battery reaches a certain value, the explosion-proof disc opens at the weakest groove, releasing the internal pressure of the battery and preventing the internal pressure from increasing further and causing the battery to explode.

[0003] Existing explosion-proof plates are usually located in the center of the battery cover or battery casing. The distance between the explosion-proof plate and the positive and negative electrodes of the battery cell is roughly the same, so that the path length of the gas and / or solid-liquid mixture ejected from the positive and negative electrodes of the battery cell to the explosion-proof plate is roughly the same. This avoids the situation where the path on one side is too long, and ensures that the gas and / or solid-liquid mixture ejected from the positive and negative electrodes of the battery cell can be discharged in time, preventing the battery from exploding or leaking.

[0004] However, for secondary batteries with a long battery casing and positive and negative terminals located on opposite sides of the casing length, if the explosion-proof plate is placed in the center of the casing, the distance from the positive and negative terminals of the cell to the explosion-proof plate is long, making it inconvenient for gas and / or solid-liquid mixtures to be discharged from the battery casing in a timely manner. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defect in the prior art where the explosion-proof sheet is placed in the center of the battery casing, resulting in a long distance between the positive and negative electrodes of the battery cell and the explosion-proof sheet, which is not conducive to the timely discharge of gas and / or solid-liquid mixture. The present invention provides a battery casing assembly and a secondary battery.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution:

[0007] A battery housing assembly includes a battery housing and an explosion-proof sheet, wherein both the battery housing and the explosion-proof sheet are made of steel.

[0008] The battery casing extends through both ends in its length direction, and the two ends of the battery casing in its length direction are used to connect with the battery cover plate.

[0009] The battery casing has two first sidewalls spaced apart in its width direction, wherein one of the first sidewalls is provided with a plurality of explosion-proof holes spaced apart along the length direction of the battery casing, the explosion-proof holes are through both ends in the width direction of the battery casing, and at least two of the explosion-proof holes are respectively provided on both sides of the first sidewall in the length direction of the battery casing.

[0010] The number of explosion-proof plates is the same as the number of explosion-proof holes and they are set in a one-to-one correspondence. The explosion-proof plates are fixed on the battery housing and cover the corresponding explosion-proof holes.

[0011] In this design, the battery casing has two ends along its length for connecting to a battery cover plate containing a positive terminal and a negative terminal, respectively. This means the positive and negative terminals of the battery cell located inside the casing are situated on opposite sides of the casing along its length. Therefore, an explosion-proof hole is provided on each side of the first sidewall along the length of the battery casing. This shortens the distance between the positive and negative terminals of the battery cell and the corresponding explosion-proof hole, allowing gases and / or solid-liquid mixtures ejected from the positive and negative terminals to be discharged from the nearest explosion-proof hole, reducing discharge time and effectively preventing battery explosion or leakage.

[0012] Preferably, the explosion-proof sheet includes a planar portion and a protruding portion. The planar portion is disposed on the outer periphery of the protruding portion. The planar portion has a first end face and a second end face that are spaced apart in the width direction of the battery housing. The protruding portion is recessed from the first end face in the width direction of the battery housing toward the second end face. The end of the protruding portion away from the first end face in the width direction of the battery housing protrudes beyond the second end face in the width direction of the battery housing.

[0013] The planar portion is welded to the first sidewall and forms a first weld; the protrusion has an explosion-proof groove on one end face in the width direction of the battery casing, and the depth of the explosion-proof groove is less than the wall thickness of the protrusion.

[0014] In this solution, a protrusion is formed on the explosion-proof sheet, so that the first weld and the explosion-proof markings are located on different parts of the explosion-proof sheet. The flat part and the protrusion are staggered in the width direction of the battery shell (i.e., the thickness direction of the explosion-proof sheet), which can effectively prevent the heat generated by welding at the first weld on the flat part from being transferred to the explosion-proof markings on the protrusion, prevent deformation at the explosion-proof markings, and prevent the explosion-proof sheet from failing.

[0015] Preferably, the protrusion is located on the side of the flat portion facing the inside of the battery housing in the width direction of the battery housing, the protrusion extends into the explosion-proof hole, and the second end face abuts against the outer wall surface of the first sidewall.

[0016] In this solution, the above-mentioned design prevents the protrusion from being exposed outside the battery casing, making it less likely for the protrusion to interfere with other structures, thus facilitating the assembly of the secondary battery and subsequent battery module assembly.

[0017] Preferably, there is a gap between the outer peripheral wall of the protrusion and the wall of the explosion-proof hole, and the shortest distance d1 between the outer peripheral wall of the protrusion and the wall of the explosion-proof hole is 0.05~0.1mm.

[0018] In this design, the aforementioned arrangement facilitates the insertion of the protrusion into the explosion-proof hole, minimizing the risk of deformation of the battery casing. Furthermore, the small gap between the protrusion and the explosion-proof hole allows for rapid positioning of the explosion-proof plate on the battery casing through their interaction, thus increasing the assembly speed.

[0019] Preferably, the distance between the end face of the protrusion away from the first end face in the width direction of the battery casing and the second end face is defined as d2, where d2 = (1~10) * t1; and t1 is the wall thickness of the protrusion.

[0020] In this solution, by reasonably controlling the protrusion height of the protrusion, it is possible to prevent the transfer of welding heat on the one hand, and to prevent the protrusion from interfering with the battery cells inside the battery casing on the other hand.

[0021] Preferably, the distance d2 between the end face of the protrusion away from the first end face in the width direction of the battery casing and the second end face is equal to the wall thickness t2 of the first sidewall.

[0022] In this design, the above-mentioned arrangement prevents the protrusion from extending into the battery casing, thereby effectively avoiding interference between the protrusion and the battery cells inside the battery casing and reserving more installation space for the battery cells.

[0023] Preferably, the wall thickness t3 of the planar portion is 0.1~1mm; and / or, the wall thickness t1 of the protrusion is 0.1~1mm.

[0024] In this design, since steel has a higher structural strength than aluminum, the thickness of the explosion-proof sheet made of steel can be designed to be smaller, thereby reducing the space occupied by the explosion-proof sheet. This allows it to be adapted to a thinner battery casing made of steel, reserving more installation space for the battery cells and increasing the battery's capacity.

[0025] Preferably, the wall thickness t3 of the planar portion is equal to the wall thickness t1 of the protrusion.

[0026] In this solution, the above-mentioned configuration allows the flat portion and the protruding portion to be directly machined from a single sheet of material with uniform thickness, which facilitates the processing of the explosion-proof sheet.

[0027] Preferably, the battery housing assembly satisfies one or more of the following conditions:

[0028] a. The shortest distance d3 between the outer peripheral wall of the planar portion and the outer peripheral end of the first weld is 1-5mm;

[0029] b. The shortest distance d4 between the outer peripheral wall of the protrusion and the inner peripheral end of the first weld is 1-5mm;

[0030] c. The shortest distance d5 between the explosion-proof groove and the inner peripheral wall of the protrusion is greater than or equal to 1 mm;

[0031] d. A second weld is provided on one side wall of the battery casing, and the second weld extends along the length of the battery casing to both ends of the battery casing.

[0032] In this design, the aforementioned arrangement provides sufficient welding space on the flat surface, ensuring the weld strength between the flat surface and the battery casing. Furthermore, increasing the distance between the flat surface and the protrusion extends the heat transfer path generated during welding, gradually dissipating the heat and resulting in lower temperatures closer to the explosion-proof notch. This further prevents deformation at the explosion-proof notch and avoids malfunction of the explosion-proof plate. The distance between the explosion-proof notch and the protrusion also provides ample machining space for processing the notch, facilitating its fabrication. The battery casing is formed by bending and welding sheet metal, a method that facilitates the processing of steel battery casings.

[0033] A secondary battery includes a battery cell, two battery cover plates, and a battery housing assembly as described above. The battery cell is disposed inside the battery housing, and the two battery cover plates are respectively fixed to both ends of the battery housing in its length direction. The positive electrode and negative electrode of the battery cell are respectively located at both ends of the battery cell in the length direction of the battery housing.

[0034] In this solution, an explosion-proof hole is provided on each side of the first sidewall along the length of the battery casing. This can shorten the distance between the positive and negative electrodes of the battery cell and the explosion-proof hole on the corresponding side, so that the gas and / or solid-liquid mixture ejected from the positive and negative electrodes of the battery cell can be discharged from the explosion-proof hole on the corresponding side nearby, shortening the discharge time and effectively preventing battery explosion or leakage.

[0035] The positive and progressive effects of this utility model are as follows: An explosion-proof hole is provided on each side of the first sidewall along the length of the battery casing, which can shorten the distance between the positive and negative electrodes of the battery cell and the explosion-proof hole on the corresponding side. As a result, the gas and / or solid-liquid mixture ejected from the positive and negative electrodes of the battery cell can be discharged from the explosion-proof hole on the corresponding side nearby, shortening the discharge time and effectively preventing the battery from exploding or leaking. Attached Figure Description

[0036] Figure 1 This is a three-dimensional structural diagram of the battery housing assembly according to an embodiment of the present utility model.

[0037] Figure 2 This is a three-dimensional structural diagram of the battery casing according to an embodiment of the present utility model.

[0038] Figure 3 This is a side view of the battery casing according to an embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the battery casing from another side of an embodiment of the present invention.

[0040] Figure 5 This is a three-dimensional structural diagram of the explosion-proof sheet according to an embodiment of the present invention.

[0041] Figure 6 This is a cross-sectional structural diagram of the explosion-proof sheet according to an embodiment of the present invention.

[0042] Figure 7 This is a partial side view of the battery housing assembly according to an embodiment of the present invention.

[0043] Figure 8 This is a cross-sectional view of the battery housing assembly according to an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] Battery casing 1

[0046] First side wall 11

[0047] Second sidewall 12

[0048] Explosion-proof hole 13

[0049] Second weld 14

[0050] Explosion-proof sheet 2

[0051] Planar part 21

[0052] First end face 211

[0053] Second end face 212

[0054] Protrusion 22

[0055] Groove 221

[0056] First weld seam 23

[0057] Explosion-proof markings 24

[0058] Installation space 3 Detailed Implementation

[0059] The present invention will be described more clearly and completely below with reference to the accompanying drawings, using a preferred embodiment.

[0060] This embodiment discloses a secondary battery, including a battery cell, a battery cover plate, and a battery casing assembly.

[0061] Specifically, such as Figure 1 and Figure 2 As shown, the battery housing assembly includes a battery housing 1, which has a square structure. The battery housing 1 has two first sidewalls 11 and two second sidewalls 12. The two first sidewalls 11 are located in the width direction of the battery housing 1. Figure 1 The two second sidewalls 12 are spaced apart in the Y direction of the battery casing 1, and are spaced apart in the thickness direction of the battery casing 1. Figure 1 The two first sidewalls 11 are spaced apart along the Z-direction of the battery casing 1. Their ends in the thickness direction are connected to the corresponding ends of the two second sidewalls 12, forming an installation space 3 for accommodating the battery cell. The positive and negative electrode plates of the battery cell are located at opposite ends of the battery cell along the length direction of the battery casing 1. The area of ​​the first sidewall 11 is smaller than the area of ​​the second sidewall 12.

[0062] Furthermore, such as Figure 1 As shown, the battery casing 1 is in its length direction ( Figure 1 The battery cell has two through-holes (in the X direction) forming an opening that connects to the mounting space 3. In this embodiment, there are two battery cover plates (not shown in the figure). Each cover plate has a positive terminal and a negative terminal. The two cover plates are fixed to both ends of the battery housing 1 along its length and seal the openings on both sides of the battery housing 1, thus sealing the mounting space 3 of the battery cell. The positive terminal of the battery cell is connected to the positive terminal of the battery cover plate, and the negative terminal of the battery cell is connected to the negative terminal of the battery cover plate.

[0063] In this embodiment, the battery casing 1 is formed by bending and welding sheet metal. This forming method facilitates the processing of the steel battery casing 1. Specifically, as shown... Figure 3 As shown, a second weld 14 is provided on one of the first sidewalls 11 of the battery housing 1. The second weld 14 extends along the length of the battery housing 1 to both ends of the battery housing 1. The second weld 14 is formed by welding the portions of the battery housing 1 located on both sides.

[0064] In other alternative embodiments, the second weld 14 may also be formed on the second sidewall 12.

[0065] like Figure 2 and Figure 4As shown, two explosion-proof holes 13 are provided on one of the first sidewalls 11 of the battery casing 1. The explosion-proof holes 13 extend through both ends in the width direction of the battery casing 1 to connect the mounting space 3 and the external space of the secondary battery. The two explosion-proof holes 13 are spaced apart along the length direction of the battery casing 1 and are respectively located on both sides of the first sidewall 11 in the length direction of the battery casing 1. The two explosion-proof holes 13 are respectively located close to the positive and negative terminals of the battery cell.

[0066] Preferably, the explosion-proof hole 13 and the second weld 14 are respectively provided on two different first sidewalls 11.

[0067] like Figure 1 and Figure 5 As shown, the battery housing assembly also includes two explosion-proof plates 2, each corresponding to one of the two explosion-proof holes 13. The explosion-proof plates 2 are fixed to the battery housing 1 and completely cover the corresponding explosion-proof holes 13. When the secondary battery is in normal condition, the explosion-proof plates 2 always seal the explosion-proof holes 13 on the battery housing 1 to ensure the airtightness of the secondary battery. When the power in the installation space 3 increases, causing pressure to rise and potentially leading to an explosion, the explosion-proof plates 2 can be ruptured in time, releasing the battery pressure within the installation space 3 through the explosion-proof holes 13, reducing the risk of explosion.

[0068] In this embodiment, an explosion-proof hole 13 is provided on both sides of the first sidewall 11 along the length direction of the battery casing 1. This can shorten the distance between the positive and negative electrodes of the battery cell and the corresponding explosion-proof hole 13, so that the gas and / or solid-liquid mixture ejected from the positive and negative electrodes of the battery cell can be discharged from the corresponding explosion-proof hole 13 nearby, shortening the discharge time and effectively preventing battery explosion or leakage.

[0069] In other alternative embodiments, the number of explosion-proof holes 13 can be greater, with multiple explosion-proof holes 13 spaced apart along the length of the battery casing 1, and at least two explosion-proof holes 13 respectively located on both sides of the first sidewall 11 along the length of the battery casing 1. This embodiment provides only two explosion-proof holes 13 to ensure the strength of the first sidewall 11 while allowing for timely discharge of gas and / or solid-liquid mixtures. When the number of explosion-proof holes 13 is different, the number of explosion-proof plates 2 also needs to be adjusted to be the same as the number of explosion-proof holes 13. Each explosion-proof plate 2 corresponds to one explosion-proof hole 13, and the explosion-proof plate 2 covers the corresponding explosion-proof hole 13.

[0070] In this embodiment, the battery casing 1, the explosion-proof sheet 2, and the battery cover are all made of steel, specifically stainless steel, such as SUS304 or SUS316L. Stainless steel is more corrosion-resistant and can improve the service life of the secondary battery. In other alternative embodiments, the battery casing 1, the explosion-proof sheet 2, and the battery cover can also be made of non-stainless steel.

[0071] Because steel has a higher structural strength than aluminum, this embodiment uses steel to make the battery casing 1, explosion-proof sheet 2, and battery cover. Under the same strength conditions, the wall thickness of the battery casing 1, explosion-proof sheet 2, and battery cover can be reduced compared to those made of traditional aluminum. With the battery casing dimensions remaining unchanged, more installation space 3 is reserved for the battery cells located inside the casing, increasing the secondary battery's capacity. Furthermore, the steel battery casing is more heat-resistant, can withstand greater pressure, and is less prone to severe burn-through, reducing the risk of heat diffusion from the battery cells.

[0072] In this embodiment, the wall thickness of the battery casing 1 and the wall thickness of the explosion-proof sheet 2 are the same, both being 0.2 mm. In other alternative embodiments, the wall thickness of the battery casing 1 and the wall thickness of the explosion-proof sheet 2 may also be different. The preferred range for the wall thickness of the battery casing 1 is 0.1~1 mm, and the preferred range for the wall thickness of the explosion-proof sheet 2 is 0.1~1 mm.

[0073] like Figures 5-8 As shown, the explosion-proof sheet 2 in this embodiment is an integral structure. The explosion-proof sheet 2 includes a flat part 21 and a protruding part 22. The flat part 21 is disposed on the outer periphery of the protruding part 22.

[0074] like Figure 6 and Figure 8 As shown, the planar portion 21 has a first end face 211 and a second end face 212 spaced apart in the width direction of the battery housing 1 (which is also the thickness direction of the explosion-proof sheet 2). The protrusion 22 is recessed from the first end face 211 toward the second end face 212 along the width direction of the battery housing 1. The protrusion 22 has a groove 221 with an opening toward the first end face 211. The end of the protrusion 22 away from the first end face 211 in the width direction of the battery housing 1 protrudes along the width direction of the battery housing 1 to extend beyond the second end face 212, so that the planar portion 21 and the protrusion 22 are misaligned in the width direction of the battery housing 1.

[0075] As shown in Figure 8, in this embodiment, the protrusion 22 is located on the side of the flat portion 21 facing the inside of the battery housing 1 in the width direction of the battery housing 1. The protrusion 22 extends into the interior of the explosion-proof hole 13, thereby preventing the protrusion 22 from being exposed outside the battery cover plate. This makes the protrusion 22 less likely to interfere with other structures, facilitating the assembly of the secondary battery and subsequent battery module assembly. The second end face 212 of the flat portion 21 abuts against the outer wall surface of the first side wall 11. The flat portion 21 is the part of the explosion-proof sheet 2 that is welded to the first side wall 11. In addition, the cooperation between the outer peripheral wall of the protrusion 22 and the hole wall of the explosion-proof hole 13 enables rapid positioning of the explosion-proof sheet 2 and the battery cover plate, improving the assembly efficiency of the battery housing assembly.

[0076] In other alternative embodiments, the protrusion 22 may also face outwards from the battery housing 1, i.e., the protrusion 22 does not extend into the explosion-proof hole 13.

[0077] Specifically, such as Figure 8 As shown, there is a gap between the outer peripheral wall of the protrusion 22 and the wall of the explosion-proof hole 13, and the shortest distance d1 between the outer peripheral wall of the protrusion 22 and the wall of the explosion-proof hole 13 is 0.05~0.1mm. On the one hand, this gap facilitates the protrusion 22 to extend into the explosion-proof hole 13, and is less likely to cause deformation of the battery housing 1. On the other hand, the small gap between the protrusion 22 and the explosion-proof hole 13 allows for rapid positioning of the explosion-proof plate 2 on the battery housing 1 through the cooperation between the protrusion 22 and the explosion-proof hole 13, thereby improving the assembly speed of both.

[0078] like Figure 6 As shown, in this embodiment, the planar portion 21 and the protruding portion 22 are directly processed from the same sheet of material with uniform thickness. Therefore, the wall thickness of the explosion-proof sheet 2 is the wall thickness t3 of the planar portion 21 and the wall thickness t1 of the protruding portion 22. That is, the wall thickness t3 of the planar portion 21 is equal to the wall thickness t1 of the protruding portion 22, both of which are 0.2mm, to facilitate the processing of the explosion-proof sheet 2.

[0079] In other alternative embodiments, the wall thickness t3 of the planar portion 21 and the wall thickness t1 of the protrusion 22 may not be equal. Alternatively, the wall thickness t3 of the planar portion 21 and the wall thickness t1 of the protrusion 22 may be designed to other values ​​according to actual needs, preferably in the range of 0.1~1mm.

[0080] like Figure 6 and Figure 7 As shown, the planar portion 21 and the first sidewall 11 are welded together using welding processes such as laser penetration welding, forming a first weld 23 in the area where the planar portion 21 and the first sidewall 11 are welded. The shortest distance d3 between the outer peripheral wall of the planar portion 21 and the outer peripheral end of the first weld 23 is 1-5 mm, and the shortest distance d4 between the outer peripheral wall of the protrusion 22 and the inner peripheral end of the first weld 23 is 1-5 mm. On the one hand, this allows sufficient welding space to be reserved on the planar portion 21, ensuring the welding strength between the planar portion 21 and the battery casing 1. On the other hand, by increasing the distance between the planar portion 21 and the protrusion 22, the heat transfer path generated by welding can be extended, gradually consuming the heat generated by welding, resulting in a lower temperature closer to the explosion-proof notch 24, further preventing deformation at the explosion-proof notch 24 and preventing the explosion-proof sheet 2 from failing.

[0081] In this embodiment, the shortest distance d3 between the outer peripheral wall of the planar portion 21 and the outer peripheral end of the first weld 23 is the same as the shortest distance d4 between the outer peripheral wall of the protrusion 22 and the inner peripheral end of the first weld 23, and the distance d6 between the outer peripheral wall of the planar portion 21 and the outer peripheral wall of the protrusion 22 is 5mm.

[0082] In other alternative embodiments, the shortest distance d3 between the outer peripheral wall of the planar portion 21 and the outer peripheral end of the first weld 23, and the shortest distance d4 between the outer peripheral wall of the protrusion 22 and the inner peripheral end of the first weld 23, can also be designed to other values ​​according to the actual situation.

[0083] Furthermore, such as Figures 5-8 As shown, the protrusion 22 has an explosion-proof groove 24 on one end face of the battery casing 1 near the first end face 211 in the width direction. The explosion-proof groove 24 is an indentation structure provided on the end face of the protrusion 22 to reduce the thickness of the protrusion 22 at the location where the explosion-proof groove 24 is provided. The depth h of the explosion-proof groove 24 in the width direction of the battery casing 1 is less than the wall thickness t1 of the protrusion 22, that is, the explosion-proof groove 24 will not penetrate the protrusion 22. The explosion-proof groove 24 is used to break open in time when the battery pressure in the secondary battery installation space 3 is too high, quickly release the pressure, and prevent explosion.

[0084] Specifically, in this embodiment, the depth h of the explosion-proof notch 24 is 0.1 mm to facilitate timely discharge of gas generated by the battery cell. In other alternative embodiments, the depth h of the explosion-proof notch 24 can also be designed to other values ​​according to actual needs, with a preferred range of 0.05~0.6 mm.

[0085] In other alternative embodiments, the explosion-proof notch 24 may also be provided on one end face of the protrusion 22 away from the first end face 211 in the width direction of the battery housing 1.

[0086] In this embodiment, the first weld 23 and the explosion-proof groove 24 of the explosion-proof sheet 2 are located in different parts of the explosion-proof sheet 2. The flat part 21 with the first weld 23 and the protruding part 22 with the explosion-proof groove 24 are misaligned in the width direction (i.e. the thickness direction of the explosion-proof sheet 2) of the battery housing 1. This can effectively prevent the heat generated by welding at the first weld on the flat part 21 from being transferred to the explosion-proof groove 24 on the protruding part 22, prevent deformation at the explosion-proof groove 24, and prevent the explosion-proof sheet 2 from failing.

[0087] Furthermore, such as Figure 6As shown, the distance between the end face of the protrusion 22 away from the first end face 211 and the second end face 212 in the width direction of the battery casing 1 is defined as d2, where d2 = (1~10) * t1. In this embodiment, by controlling the height difference between the flat portion 21 and the protrusion 22 in the width direction of the battery casing 1 within a certain range, on the one hand, it avoids the heat generated at the first weld 23 from being easily transferred to the explosion-proof notch 24 on the protrusion 22 due to an excessively low height difference, thus preventing deformation of the explosion-proof notch 24 and preventing the explosion-proof sheet 2 from failing. On the other hand, it avoids the protrusion 22 from excessively extending into the battery and interfering with the cell due to an excessively high height difference, ensuring the reliability of the secondary battery; or it avoids the protrusion 22 from excessively protruding from the outside of the battery and occupying too much space due to an excessively high height difference, thereby making the structure of the secondary battery more compact.

[0088] In other alternative embodiments, the distance d2 between the end face of the protrusion 22 away from the first end face 211 in the width direction of the battery housing 1 and the second end face 212 can also be designed to other values ​​according to actual needs.

[0089] Specifically, such as Figure 8 As shown, in this embodiment, the distance d2 between the end face of the protrusion 22 away from the first end face 211 in the width direction of the battery housing 1 and the second end face 212 is equal to the wall thickness t2 of the first side wall 11, so that the protrusion 22 will not extend into the interior of the battery housing 1, thereby effectively avoiding interference between the protrusion 22 and the battery cell inside the battery housing 1, and reserving a larger installation space 3 for the battery cell.

[0090] Furthermore, such as Figure 6 As shown, the shortest distance d5 between the explosion-proof notch 24 and the inner peripheral wall of the protrusion 22 is greater than or equal to 1 mm, providing sufficient machining space for processing the explosion-proof notch 24 and facilitating its machining. Specifically, the shortest distance d5 between the explosion-proof notch 24 and the inner peripheral wall of the protrusion 22 can be the distance between them in the width or length direction of the explosion-proof sheet 2.

[0091] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship of the device or component shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0092] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of this utility model is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of this utility model, but all such changes and modifications fall within the scope of protection of this utility model.

Claims

1. A battery casing assembly, characterized in that, The battery housing assembly includes a battery housing and an explosion-proof sheet, both of which are made of steel. The battery casing extends through both ends in its length direction, and the two ends of the battery casing in its length direction are used to connect with the battery cover plate. The battery casing has two first sidewalls spaced apart in its width direction, wherein one of the first sidewalls is provided with a plurality of explosion-proof holes spaced apart along the length direction of the battery casing, the explosion-proof holes are through both ends in the width direction of the battery casing, and at least two of the explosion-proof holes are respectively provided on both sides of the first sidewall in the length direction of the battery casing. The number of explosion-proof plates is the same as the number of explosion-proof holes and they are set in a one-to-one correspondence. The explosion-proof plates are fixed on the battery housing and cover the corresponding explosion-proof holes.

2. The battery casing assembly as claimed in claim 1, characterized in that, The explosion-proof sheet includes a planar portion and a protruding portion. The planar portion is disposed on the outer periphery of the protruding portion. The planar portion has a first end face and a second end face that are spaced apart in the width direction of the battery housing. The protruding portion is recessed from the first end face in the width direction of the battery housing toward the second end face. The end of the protruding portion away from the first end face in the width direction of the battery housing protrudes out of the second end face in the width direction of the battery housing. The planar portion is welded to the first sidewall and forms a first weld; the protrusion has an explosion-proof groove on one end face in the width direction of the battery casing, and the depth of the explosion-proof groove is less than the wall thickness of the protrusion.

3. The battery casing assembly as described in claim 2, characterized in that, The protrusion is located on the side of the flat portion facing the inside of the battery housing in the width direction of the battery housing. The protrusion extends into the explosion-proof hole, and the second end face abuts against the outer wall surface of the first side wall.

4. The battery casing assembly as claimed in claim 3, characterized in that, There is a gap between the outer peripheral wall of the protrusion and the wall of the explosion-proof hole, and the shortest distance d1 between the outer peripheral wall of the protrusion and the wall of the explosion-proof hole is 0.05~0.1mm.

5. The battery casing assembly as claimed in claim 3, characterized in that, The distance between the end face of the protrusion away from the first end face and the second end face in the width direction of the battery casing is defined as d2, where d2 = (1~10) * t1; and t1 is the wall thickness of the protrusion.

6. The battery housing assembly as claimed in claim 5, characterized in that, The distance d2 between the end face of the protrusion away from the first end face in the width direction of the battery casing and the second end face is equal to the wall thickness t2 of the first sidewall.

7. The battery housing assembly as claimed in claim 2, characterized in that, The wall thickness t3 of the planar portion is 0.1~1mm; and / or the wall thickness t1 of the protruding portion is 0.1~1mm.

8. The battery housing assembly as claimed in claim 7, characterized in that, The wall thickness t3 of the planar portion is equal to the wall thickness t1 of the protruding portion.

9. The battery casing assembly as described in any one of claims 2-8, characterized in that, The battery housing assembly satisfies one or more of the following conditions: a. The shortest distance d3 between the outer peripheral wall of the planar portion and the outer peripheral end of the first weld is 1-5mm; b. The shortest distance d4 between the outer peripheral wall of the protrusion and the inner peripheral end of the first weld is 1-5mm; c. The shortest distance d5 between the explosion-proof groove and the inner peripheral wall of the protrusion is greater than or equal to 1 mm; d. A second weld is provided on one side wall of the battery casing, and the second weld extends along the length of the battery casing to both ends of the battery casing.

10. A secondary battery, characterized in that, The secondary battery includes a cell, two battery cover plates, and a battery housing assembly as described in any one of claims 1-9. The cell is disposed inside the battery housing, and the two battery cover plates are respectively fixed to both ends of the battery housing in its length direction. The positive electrode and negative electrode of the cell are respectively located at both ends of the cell in the length direction of the battery housing.

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