Power battery module shell and power battery

Abstract

The utility model relates to the technical field of battery modules, and discloses a power battery module shell and a power battery. The power battery module shell comprises a frame structure formed by welding a first end plate, a first side plate, a second end plate and a second side plate end to end; at least one of the first end plate, the second end plate, the first side plate and the second side plate is a magnesium alloy plate; and a corrosion-resistant protective layer is formed in a welding area of the magnesium alloy plate. The weight of the power battery pack can be reduced; the corrosion-resistant protective layer is formed in the welding area of the magnesium alloy plate, so that the base metal is protected, and the corrosion resistance of the welding seam is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of battery modules, in particular to a power battery module housing and a power battery. Background Art

[0002] In the past five years, new energy electric vehicles have been booming, and driving range has become a major concern for consumers. Driving range is determined by the power battery pack, the core component of new energy electric vehicles.

[0003] A single power battery pack consists of at least two battery modules. Currently, the end plates and side plates on the power battery module housing are made of a density of 2.7g / cm 3 The battery pack is made of aluminum alloy materials, and the weight of the entire battery pack is relatively heavy, which is not conducive to improving the cruising range of electric vehicles.

[0004] The welds between the end plates and side plates of the power battery module housing in the related art have poor corrosion resistance and are prone to corrosion, which affects the service life of the power battery module housing. Utility Model Content

[0005] In view of this, the present invention provides a power battery module housing and a power battery to solve the problems of heavy weight of the power battery module housing and easy corrosion at the welds.

[0006] In the first aspect, the utility model provides a power battery module housing, including an end plate and a side plate, the end plate including a first end plate and a second end plate, the side plate including a first side plate and a second side plate, the first end plate, the first side plate, the second end plate and the second side plate are welded end to end to form a frame structure, and the ends of the first end plate, the first side plate, the second end plate and the second side plate have welding areas; at least one of the first end plate, the second end plate, the first side plate and the second side plate is a magnesium alloy plate; the welding area of ​​the magnesium alloy plate is formed with a corrosion-resistant protective layer.

[0007] Beneficial effect: Since the density of magnesium alloy material is 1.74~1.85g / cm 3 , approximately one-third lighter than aluminum alloy, and boasting superior strength and stiffness. Therefore, in a power battery module housing, at least one of the first end plate, second end plate, first side plate, and second side plate is a magnesium alloy plate, effectively reducing the weight of the power battery pack. Because magnesium alloy plates are used to manufacture power battery module housings, the parent material surface at the weld and its surrounding areas is susceptible to damage during laser welding. Therefore, forming a corrosion-resistant protective layer in the weld area of ​​the magnesium alloy plate protects the parent material and improves the corrosion resistance of the weld.

[0008] In an optional embodiment, the corrosion-resistant protective layer is one or more of an AlSi30 layer, a Zr layer, a Cu layer, a Ni layer, an Al layer, and a TiC layer.

[0009] Beneficial effect: During welding, AlSi30, Zr-Cu-Ni-Al / TiC and other powders are sent to the welding area of ​​the magnesium alloy plate, so that the corrosion-resistant powder can be melted on the surface of the weld to form a protective layer. The protective layer after melting contains one or more of AlSi30, Zr, Cu, Ni, Al, and TiC, which can protect the base material and improve the corrosion resistance of the weld.

[0010] In an optional embodiment, at least one of the first end plate, the second end plate, the first side plate, and the second side plate is a magnesium-aluminum alloy plate.

[0011] Beneficial effect: With this arrangement, the same plate is made of two kinds of metal, which reduces the weight while ensuring the strength.

[0012] In an optional embodiment, at least one middle side panel is further included, and the first end panel and / or the second end panel are provided with a plug-in slot adapted to the middle side panel, the end portion of the middle side panel is plugged into the plug-in slot, and the end portion of the middle side panel has two opposite side edges in the extension direction of the end panel, and one of the side edges is welded to the inner wall of the plug-in slot.

[0013] Beneficial effect: The two ends of the middle side plate are connected to the first end plate and / or the second end plate by plugging, which can play a role in preliminary positioning and fixing, and then the middle side plate and the first end plate and the second end plate can be fixed by welding.

[0014] In an optional embodiment, the middle side plate is a magnesium alloy plate.

[0015] Beneficial effect: The middle side panel is made of magnesium alloy material, which can reduce the weight of the middle side panel, thereby further reducing the weight of the power battery module casing.

[0016] In an optional embodiment, at least one end of the side panel is bent to form a rim, which covers at least a portion of the end panel connected thereto, and the rim and the end panel are welded; the radius of the bent corner of the rim is r, the thickness of the side panel is d, and r≥3d.

[0017] Beneficial Effects: Hemming is another method for joining end and side panels. In this case, tailor welding can be used to secure the end and side panels. This provides a secure, reliable connection at a low cost. The bend radius is controlled within a range of three times or more of the side panel thickness, ensuring a more reasonable fillet radius and further reducing the risk of cracking in the magnesium alloy sheet during bending.

[0018] In an optional embodiment, the side plate is a magnesium alloy plate, and the edge wrapping is formed by bending the side plate along a bending line perpendicular to the rolling direction of the magnesium alloy plate.

[0019] Beneficial effect: By bending the magnesium alloy plate along a bending line perpendicular to the rolling direction to form an edge, the risk of cracking of the magnesium alloy plate during bending can be reduced.

[0020] In an optional embodiment, a protrusion is provided at the tail of the welding area of ​​the side plate, the height of the protrusion is 1±0.5 mm, or the length is 5±2 mm, and the protrusion can be melted to fill the pit formed at the end of welding.

[0021] Beneficial effect: By setting the protrusions, the protrusions can be used to fill the pits to avoid welding breakdown. At the same time, the welding power at the protrusions is reduced to 45% to 75% of the welding power at other positions to reduce the energy at the tail of the weld, which can effectively prevent the problem of breakdown at the end of laser welding.

[0022] In an optional embodiment, the magnesium alloy plate is subjected to grinding, micro-arc oxidation, spray coating or passivation treatment.

[0023] Beneficial effects: The corrosion resistance of the product can be improved by surface treatment of the magnesium alloy plate by means of sandblasting, micro-arc oxidation, spraying, passivation, etc.

[0024] In a second aspect, the present invention further provides a power battery, comprising a power battery module housing according to any one of the above technical solutions.

[0025] Beneficial effects: Since the power battery includes the above-mentioned power battery module casing, it has the same effects as the power battery module casing, which will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of a bending line in a power battery module housing according to an embodiment of the present utility model;

[0028] Figure 2 This is a schematic structural diagram of a heating area in a power battery module housing according to an embodiment of the present utility model;

[0029] Figure 3This is a schematic structural diagram of a power battery module housing bent by a bending die in an embodiment of the utility model;

[0030] Figure 4 This is a schematic structural diagram of a power battery module housing according to an embodiment of the present utility model;

[0031] Figure 5 This is a schematic structural diagram of a power battery module according to an embodiment of the present utility model;

[0032] Figure 6 for Figure 5 A top view of

[0033] Figure 7 for Figure 6 Schematic diagram of the local enlarged structure at A in the middle;

[0034] Figure 8 It is a partial enlarged structural diagram of the lap welding between the side plate and the end plate;

[0035] Figure 9 for Figure 5 Front view of

[0036] Figure 10 For the Figure 9 Cross-sectional view along DD;

[0037] Figure 11 for Figure 10 Schematic diagram of the local enlarged structure at B in the middle;

[0038] Figure 12 Schematic diagram of the structure of the nozzle inner hole;

[0039] Figure 13 It is a structural diagram of the welding area;

[0040] Figure 14 Set up a raised side view for the tail of the weld area;

[0041] Figure 15 for Figure 14 Schematic diagram of the locally enlarged structure at point C in the middle.

[0042] Description of reference numerals:

[0043] 1. First end plate; 2. Second end plate; 3. First side plate; 4. Second side plate; 5. Middle side plate; 6. Edging; 7. Insertion slot; 8. Nozzle; 9. Welding seam; 10. Bending line; 20. Heating area; 30. Welding area; 310. Protrusion; 100. Power battery module; 300. Bending mold; 301. First mold; 302. Second mold. DETAILED DESCRIPTION

[0044] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0045] The following combination Figures 1 to 15 , describing the embodiments of the present utility model.

[0046] According to an embodiment of the present invention, a power battery module housing is provided. Figure 4 As shown, the power battery module housing includes end plates and side plates, the end plates include a first end plate 1 and a second end plate 2, the side plates include a first side plate 3 and a second side plate 4, and the first end plate 1, the first side plate 3, the second end plate 2 and the second side plate 4 are welded end to end to form a frame structure; the welding position of the first end plate 1, the second end plate 2, the first side plate 3 and the second side plate 4 is at the end, that is, the end is provided with a welding area 30; at least one of the first end plate 1, the second end plate 2, the first side plate 3 and the second side plate 4 is a magnesium alloy plate; the welding area 30 corresponding to the magnesium alloy plate is formed with a corrosion-resistant protective layer.

[0047] Since magnesium alloys have a density of 1.74 to 1.85 g / cm³, they are approximately one-third lighter than aluminum alloys and possess higher strength and stiffness than aluminum alloys. Therefore, in the power battery module housing, at least one of the first end plate 1, second end plate 2, first side plate 3, second side plate 4, and middle side plate 5 is a magnesium alloy plate, effectively reducing the weight of the power battery pack. Since magnesium alloy plates are used to make the power battery module housing, the surface of the parent material in the weld area 30, i.e., weld seam 9, and its vicinity, is susceptible to damage during laser welding. Therefore, forming a corrosion-resistant protective layer in the weld area of ​​the magnesium alloy plates, i.e., on the surface of weld seam 9 and its vicinity, can protect the parent material and improve the corrosion resistance of the weld.

[0048] Specifically, the magnesium alloy material includes grades such as AZ31B or AZ91D, and has a tensile strength of 220 to 260 MPa.

[0049] In one embodiment, at least one of the first end plate 1 , the second end plate 2 , the first side plate 3 , and the second side plate 4 is a magnesium-aluminum alloy plate.

[0050] This setup uses two types of metal to create the same panel, reducing weight while ensuring strength.

[0051] In one embodiment, the connection parts of the first end plate 1 , the second end plate 2 , the first side plate 3 and the second side plate 4 are made of the same material.

[0052] The connection parts between the plates are set to the same material to facilitate welding connection between the two.

[0053] In one embodiment, the first end plate 1, the second end plate 2, the first side plate 3 and the second side plate 4 of the power battery module housing are all magnesium alloy plates, which can greatly reduce the weight of the power battery pack and help improve the cruising range of the electric vehicle.

[0054] In one embodiment, the corrosion-resistant protective layer is one or more of an AlSi30 layer, a Zr layer, a Cu layer, a Ni layer, an Al layer, and a TiC layer. Corrosion-resistant powders such as AlSi30, a Zr-Cu-Ni-Al-TiC composite powder, etc. can be used as welding additive powders in advance, and the corrosion-resistant powders can be melted by laser surface cladding technology to make the corrosion-resistant layer contain one or more of AlSi30, Zr, Cu, Ni, Al, and TiC, or form a layered structure such as an AlSi30 layer, a Zr layer, a Cu layer, a Ni layer, an Al layer, and a TiC layer. Specifically, the nozzle 8 of the welding fixture can be used to deliver the corrosion-resistant powder to the weld surface and the surrounding area of ​​the magnesium alloy plate, so that the corrosion-resistant powder is clad on the weld surface to form a protective layer, which protects the parent material and improves the corrosion resistance of the weld 9.

[0055] In one embodiment, Figure 12 As shown, along the welding direction shown by F2, a protrusion 310 is provided at the tail of the welding area 30, and the height H of the protrusion 310 is controlled within the range of 1±0.5 mm, and the length L3 of the protrusion 310 is controlled within the range of 5±2 mm. The protrusion 310 can be used to fill the pit to avoid welding breakdown. At the same time, the welding power at the protrusion 310 is reduced to 45% to 75% of the welding power at other positions to reduce the energy at the tail of the weld 9, which can effectively prevent the problem of breakdown at the end during laser welding.

[0056] In one embodiment, Figure 8 As shown, both ends of the first side plate 3 are overlapped with the first end plate 1 and the second end plate 2 and are penetrated and welded; both ends of the second side plate 4 are overlapped with the first end plate 1 and the second end plate 2 and are penetrated and welded.

[0057] Overlap is a method of joining end panels and side panels. In this case, through-welding is used to secure the end panels and side panels together. This provides a secure and reliable connection at a low cost.

[0058] In one embodiment, Figures 9 to 11, and also includes at least one middle side plate 5. The first end plate 1 and / or the second end plate 2 are provided with a plug-in slot 7 adapted to the middle side plate 5. The end of the middle side plate 5 is plugged into the plug-in slot 7. The end of the middle side plate 5 has two opposite side edges in the extension direction of the end plate, and one of the side edges is welded to the inner wall of the plug-in slot 7.

[0059] The ends of the middle side panel 5 are connected to the first and second end panels 1 and 2 by plugging, which provides initial positioning and fixation. Welding then secures the middle side panel 5 to the first and second end panels 1 and 2. Because the first end of the middle side panel 5 is plugged into the plug slot 7 of the first end panel 1, both sides of the middle side panel 5 are connected to the first end panel 1. Therefore, either side of the middle side panel 5 can be welded to the first end panel 1. The second end of the middle side panel 5 is plugged into the plug slot 7 of the second end panel 2. Similarly, either side of the middle side panel 5 can be welded to the second end panel 2.

[0060] In one embodiment, the middle side plate 5 is made of a magnesium alloy plate.

[0061] The middle side plate 5 is made of a magnesium alloy plate, which can reduce the weight of the middle side plate 5 and thus further reduce the weight of the power battery module housing.

[0062] In one embodiment, Figures 5 to 7 As shown, at least one end of the side panel is bent to form a rim 6, which covers at least a portion of the end panel connected thereto, and the rim 6 and the end panel are welded; the radius of the bend of the rim 6 is r, the thickness of the side panel is d, and r≥3d.

[0063] Hemming 6 is another method for joining the end and side panels. In this case, tailor welding can be used to secure the end and side panels. This provides a secure, reliable connection at a low cost. The bend radius is controlled within a range of three times or more of the side panel thickness to ensure a more reasonable fillet radius and further reduce the risk of cracking in the magnesium alloy sheet during bending.

[0064] In one embodiment, the edge 6 is formed by bending, wherein the first side plate 3 or the second side plate 4 is a magnesium alloy plate, and the edge 6 is formed by bending the side plate along a bending line 10 perpendicular to the rolling direction of the magnesium alloy plate.

[0065] Since magnesium alloy material has a close-packed hexagonal crystal structure, magnesium alloy side panels will crack during conventional cold bending. Therefore, by setting a bending line 10 perpendicular to the rolling direction of the magnesium alloy sheet, as shown in FIG. Figure 1 As shown, bending the side plate along the bending line 10 can reduce the risk of cracking of the magnesium alloy plate during bending. Figure 1 In the direction F1.

[0066] In one embodiment, Figure 2As shown, before bending the magnesium alloy plate, a heating area 20 with a width of W3 extending from the bending line 10 to both sides is determined, and W3 is in the range of 10 mm to 20 mm. The heating area 20 is heated, and the heating temperature is controlled in the range of 200°C to 300°C.

[0067] By heating the heating area 20 and controlling the heating area 20 to extend from the bending line 10 to both sides with a width of 10 mm to 20 mm, and controlling the heating temperature to be within the range of 200°C to 300°C, the risk of cracking of the magnesium alloy plate during bending can be further reduced.

[0068] Furthermore, in one embodiment, adding a process cut at the bending portion can avoid root fracture.

[0069] In order to improve the bending efficiency and product consistency, a special bending die 300 can be designed to bend multiple side panels at the same time. Figure 3 As shown, the bending die 300 includes a first die 301 and a second die 302 that cooperate with each other. At the same time, by improving the cross-sectional quality of the sheared (punched) blank and reducing the roughness of the working surface of the bending die 300, the processing quality of the side panel can be improved.

[0070] In one embodiment, the magnesium alloy plate is subjected to grinding, micro-arc oxidation, spraying and passivation treatments.

[0071] Currently, magnesium alloys such as AZ31B and AZ91D have poorer corrosion resistance than aluminum alloys. Therefore, surface treatments such as sandblasting, micro-arc oxidation, spraying, and passivation can improve the corrosion resistance of magnesium alloy plates. In addition, magnesium alloys with the designation AZ91X can be used, as they offer excellent corrosion resistance and require no surface treatment.

[0072] In one embodiment, the welding equipment is equipped with a 4000W+2000W annular spot laser and a swingable galvanometer lens, and welding is performed using swinging modes such as ∞, 8, circular, and sine.

[0073] In one embodiment, the first end plate 1 and the second end plate 2 are both magnesium alloy plates, which are made of magnesium alloy material through an extrusion or die-casting process.

[0074] The extrusion process creates a more intense triaxial compressive stress state than forging or rolling, allowing the metal to maximize its plasticity. This is particularly important for magnesium alloys, which have poor plastic deformation capabilities. Extrusion effectively refines the grain structure of magnesium alloys, improving their strength and plasticity. The extrusion process is flexible and easy to operate. A single machine can produce a variety of plates, tubes, bars, and profiles simply by changing the die, allowing products of various shapes to be formed in a single process. Extrusion is a production method that meets market demands for a wide variety of products, specifications, small batches, and short delivery times. It produces products with high dimensional accuracy and excellent surface quality.

[0075] Magnesium alloys offer excellent die-casting performance: Their low viscosity and excellent fluidity make them easy to fill complex mold cavities. Magnesium alloys can easily produce die-cast parts with wall thicknesses of 1.0 to 2.0 mm, with the minimum wall thickness now reaching 0.6 mm. The casting slope for magnesium die-castings is 1.5 degrees, compared to 2 to 3 degrees for aluminum alloys. The dimensional accuracy of magnesium die-castings is 50% higher than that of aluminum die-castings. Magnesium alloys have lower melting points and latent heats of crystallization than aluminum alloys, resulting in less die erosion during the die-casting process and a lower die-sticking rate. Their die life can be two to four times longer than that of aluminum alloy parts. The die-casting cycle for magnesium alloy parts is shorter than that for aluminum parts, resulting in a 25% increase in production efficiency. Magnesium alloy castings also offer superior machinability, with cutting speeds up to 50% higher and energy consumption 50% lower than for aluminum alloy parts.

[0076] In one embodiment, a weld seam 9 is welded at each welding position, and the welding trajectory of each weld seam 9 is a straight line. The length of the weld seam 9 is determined according to the expansion force requirement of the power battery module 100 .

[0077] Specifically, the weld length is linearly correlated with the battery expansion force: the longer the weld length, the greater the battery expansion force it can withstand; conversely, the shorter the weld length, the smaller the battery expansion force it can withstand. Therefore, the length of the weld seam 9 can be determined based on the expansion force requirements of the power battery module 100. This can meet the expansion force requirements of the power battery module 100.

[0078] Since magnesium alloy laser welding may cause combustion and fire, in order to solve this technical problem, in one embodiment, Figure 12 As shown, it also includes a nozzle 8, which is used to press the workpiece to be welded on the welding fixture. The width of the inner hole of the nozzle 8 is W1, and the width of the weld 9 is W2, W1-W2=2X, X is in the range of 1.5mm to 4mm; the length of the inner hole of the nozzle 8 is L1, and the length of the weld 9 is L2, L1-L2=2Y, Y is in the range of 5mm to 7mm; during welding, inert gas is used as the shielding gas.

[0079] By limiting the size of the inner hole of nozzle 8, controlling X to be greater than 1.5 mm and Y to be greater than 5 mm, it is possible to ensure that nozzle 8 does not block the welding laser. At the same time, controlling X to be less than 4 mm and Y to be less than 7 mm can ensure that the shielding gas can effectively protect weld 9. Specifically, the shielding gas is an inert gas, and argon is preferably used among the inert gases.

[0080] Specifically, the flow rate of the shielding gas is set at 5 to 20 L / min, and the shielding gas is used to form a closed space at the weld 9 position to isolate the oxygen in the air, so that the magnesium element cannot burn; at the same time, it can reduce the welding heat input, avoid direct breakdown of the thin plate and cause flames, and ensure the safety and reliability of the magnesium alloy plate processing process.

[0081] In one embodiment, after welding is completed, the weld 9 is cut using a metallographic cutting machine; polished using a grinder; then the cross section of the weld 9 is corroded using a magnesium alloy metallographic structure testing liquid; finally, a macroscopic metallographic examination of the weld 9 is performed with the aid of a microscope magnifying glass (30 to 50 times) to observe the penetration depth, penetration width, and internal quality of the weld 9.

[0082] In one embodiment, the welding process conditions are as follows:

[0083] ① Before welding, you need to use alcohol to wipe clean the welding area 30 of the first end plate 1, the second end plate 2, the first side plate 3, the second side plate 4 and the middle side plate 5, or ask the supplier to clean the surface before receiving the materials;

[0084] ② The assembly clearance for welding is required to be ≤0.3mm;

[0085] ③ Use the nozzle 8 of the welding tool to press the first end plate 1, the second end plate 2, the first side plate 3, the second side plate 4 and the middle side plate 5 on the power battery module 100.

[0086] According to an embodiment of the present invention, in a second aspect, a power battery is further provided, comprising the power battery module housing according to any one of the above embodiments.

[0087] Because the power battery includes the power battery module housing of the above embodiment, it has the same effect as the power battery module housing, and will not be described in detail here.

[0088] According to an embodiment of the present utility model, in a third aspect, a battery pack is further provided, comprising the power battery in the above technical solution.

[0089] In one embodiment, the first end plate 1 , the second end plate 2 , the first side plate 3 , the second side plate 4 and the middle side plate 5 of each power battery module housing are all magnesium alloy plates.

[0090] Take the SX5G power reduction project as an example to calculate the weight reduction of the power battery:

[0091] A single power battery pack consists of six power battery modules 100. Each power battery module housing has a first end plate 1, a second end plate 2, a middle side plate 5, a first side plate 3, and a second side plate 4. The unit weights are 477g, 477g, 619.3g, 512g, and 512g, respectively. The density of magnesium alloy is approximately two-thirds that of aluminum alloy.

[0092] The weight G1 of an aluminum alloy power battery module housing is:

[0093] G1=477+477+619.3+512×2=4170.6(g).

[0094] The weight G2 of the aluminum alloy battery pack shell is 6 times the weight G1 of a single aluminum alloy power battery module shell, that is, G2×6=25023.6 (g).

[0095] The weight G3 of the battery pack casing made of magnesium alloy is two-thirds of the weight G2 of the battery pack casing made of aluminum alloy, that is, G3 = G2 × 2 / 3 = 16682.4 (g).

[0096] The reduced weight G4 of the battery pack case is one-third of the weight G2 of the aluminum alloy battery pack case, that is, G4 = G2 × 1 / 3 = 8341.2 (g).

[0097] It can be seen that the use of magnesium alloy to make the power battery module shell can greatly reduce the weight of the battery pack, which is beneficial to improving the cruising range of electric vehicles.

[0098] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A power battery module housing, characterized in that: The invention comprises an end plate and a side plate, wherein the end plate comprises a first end plate (1) and a second end plate (2), and the side plate comprises a first side plate (3) and a second side plate (4); the first end plate (1), the first side plate (3), the second end plate (2) and the second side plate (4) are welded end to end to form a frame structure, and the ends of the first end plate (1), the first side plate (3), the second end plate (2) and the second side plate (4) have welding areas (30); The two ends of the first side plate (3) are respectively overlapped with the first end plate (1) and the second end plate (2) and are penetrated and welded; the two ends of the second side plate (4) are respectively overlapped with the first end plate (1) and the second end plate (2) and are penetrated and welded; At least one of the first end plate (1), the second end plate (2), the first side plate (3) and the second side plate (4) is a magnesium alloy plate; The welding area (30) of the magnesium alloy plate is formed with a corrosion-resistant protective layer; A protrusion (310) is provided at the tail of the welding area (30) of the side plate. The height of the protrusion (310) is 1±0.5 mm, or the length is 5±2 mm. The protrusion (310) can be melted to fill the pit formed at the end of welding.

2. The power battery module housing according to claim 1, characterized in that: The corrosion-resistant protective layer is one or more of an AlSi30 layer, a Zr layer, a Cu layer, a Ni layer, an Al layer, and a TiC layer.

3. The power battery module housing according to claim 1 or 2, characterized in that: At least one of the first end plate (1), the second end plate (2), the first side plate (3) and the second side plate (4) is a magnesium-aluminum alloy plate.

4. The power battery module housing according to claim 1 or 2, characterized in that: It also includes at least one middle side plate (5), the first end plate (1) and / or the second end plate (2) are provided with a plug-in slot (7) adapted to the middle side plate (5), the end of the middle side plate (5) is plugged into the plug-in slot (7), the end of the middle side plate (5) has two opposite side edges in the extension direction of the end plate, and one of the side edges is welded to the inner side wall of the plug-in slot (7).

5. The power battery module housing according to claim 4, characterized in that: The middle side plate (5) is a magnesium alloy plate.

6. The power battery module housing according to claim 1 or 2, characterized in that: At least one end of the side plate is bent to form a rim (6), the rim (6) covers at least a portion of the end plate connected thereto, and the rim (6) and the end plate are welded; the radius of the bend of the rim (6) is r, the thickness of the side plate is d, and r≥3d.

7. The power battery module housing according to claim 6, characterized in that: The side plate is a magnesium alloy plate, and the edge wrapping (6) is formed by bending the side plate along a bending line (10) perpendicular to the rolling direction of the magnesium alloy plate.

8. The power battery module housing according to claim 1 or 2, characterized in that: The magnesium alloy plate is subjected to grinding, micro-arc oxidation, spray coating or passivation treatment.

9. A power battery, characterized in that: A power battery module housing comprising the power battery module housing according to any one of claims 1 to 8.

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