A lower plastic part and top cover assembly structure for power battery and power battery

Abstract

The present invention belongs to the technical field of batteries, and specifically relates to a lower plastic part for a power battery, a first plastic part (1) for spacing a battery cell (9) and a top cover sheet (8); and a second plastic part (2) connected to the first plastic part (1); wherein the lower plastic part has an installation state and a pre-installation state, wherein when in the installation state, the second plastic part (2) moves to a position in the same direction as the first plastic part (1). The present invention can simplify the assembly steps, help reduce manufacturing costs, reduce overall dimensional errors, and improve the overall assembly effect of the battery. In addition, the present invention also discloses a top cover assembly structure and a power battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a lower plastic part and a top cover assembly structure for a power battery and a power battery. Background Art

[0002] Power batteries generally include a top cover, a battery cell, a shell, and a plastic under the top cover. The battery cell is fixed in the shell, and a pole piece extends from the top of the battery cell to connect to the pole fixed on the top cover. The plastic under the top cover is installed under the top cover, and the top cover and the battery cell are insulated and separated by the plastic under the top cover. During assembly, the positive and negative pole tabs can be welded to the pole first, and then the battery cell is placed in the shell and the battery top cover is installed. To prevent contact between the battery cell and the pole, a pole tab pad is used to ensure a certain safety distance between the battery cell and the pole.

[0003] However, due to the addition of the tab pad, the corresponding manufacturing process and assembly steps need to be increased; on the one hand, the processing and assembly process are more complicated, and it is easy to cause the tab pad to be missed during the assembly process; on the other hand, the error in the manufacturing process of the tab pad and the assembly error between the tab pad and the lower plastic are easy to affect the assembly effect. Summary of the invention

[0004] One of the purposes of the present invention is to provide a lower plastic part for a power battery in view of the deficiencies in the prior art, which can simplify the assembly steps, help reduce manufacturing costs, reduce overall dimensional errors, and improve the overall assembly effect of the battery.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A lower plastic part for a power battery, comprising:

[0007] A first plastic part, used for separating the battery cell and the top cover sheet;

[0008] a second plastic part connected to the first plastic part;

[0009] The lower plastic part has an installation state and a pre-installation state, wherein when in the installation state, the second plastic part moves to a position in the same direction as the first plastic part.

[0010] As an improvement of the lower plastic part for a power battery described in the present invention, the first plastic part and the second plastic part are an integrally formed structure.

[0011] As an improvement of the lower plastic part for a power battery described in the present invention, at least one end portion of the first plastic part extends outward to form the second plastic part.

[0012] As an improvement of the lower plastic part for a power battery described in the present invention, the first plastic part extends outward at any point between its two ends to form the second plastic part.

[0013] As an improvement of the lower plastic part for a power battery described in the present invention, one end of the first plastic part and the second plastic part are hinged, riveted or ultrasonically connected.

[0014] As an improvement of the lower plastic part for a power battery described in the present invention, the second plastic part is fixedly connected to the first plastic part after being turned over, and the fixed connection method includes at least one of the following: snap connection, bonding, heat welding and ultrasonic connection.

[0015] As an improvement of the lower plastic part for a power battery described in the present invention, at least one of the first plastic part and the second plastic part is provided with a clamping portion and / or a buckle portion, and the first plastic part is buckled and connected to the second plastic part.

[0016] As an improvement of the lower plastic part for a power battery described in the present invention, at least one of the first plastic part and the second plastic part is provided with an adhesive layer and / or an adhesive surface, and the first plastic part is bonded to the second plastic part.

[0017] As an improvement of the lower plastic part for a power battery described in the present invention, at least one of the first plastic part and the second plastic part is provided with a heat melting column and / or a heat melting groove, and the first plastic part and the second plastic part are heat-melted.

[0018] As an improvement of the lower plastic part for a power battery described in the present invention, a bending portion is provided between the first plastic part and the second plastic part, the second plastic part can be folded toward the first plastic part along the bending portion, and the bending portion is completely disconnected or connected at least at one point after the second plastic part is folded.

[0019] As an improvement of the lower plastic part for a power battery described in the present invention, the thickness of the bent portion is smaller than the thickness of the first plastic part or the thickness of the second plastic part.

[0020] As an improvement of the lower plastic part for a power battery described in the present invention, the bending portion is provided with at least one of a fracture line, a disconnection groove and a disconnection hole, and the bending portion is connected or disconnected after the second plastic part is folded.

[0021] As an improvement of the lower plastic part for a power battery described in the present invention, the second plastic part is provided with upwardly inclined inclined surfaces along the front and rear side edges, and the inclined surfaces are planes or downwardly convex curved surfaces.

[0022] As an improvement of the lower plastic part for a power battery described in the present invention, chamfered corners are provided on the upper and lower side edges of the inclined surfaces on both sides of the second plastic part.

[0023] As an improvement of the lower plastic part for a power battery described in the present invention, the first plastic part is broken into two parts along the middle, and at least one end of each part extends outward to form the second plastic part.

[0024] As an improvement of the lower plastic part for a power battery described in the present invention, the first plastic part is provided with explosion-proof valve vents corresponding to the explosion-proof valve, and / or the second plastic part is provided with explosion-proof valve vents corresponding to the explosion-proof valve.

[0025] As an improvement of the lower plastic part for a power battery of the present invention, the ratio of the contact area between the second plastic part and the top surface of the battery cell to the total area of ​​the top surface of the battery cell is greater than 50%.

[0026] As an improvement of the lower plastic part for a power battery described in the present invention, at least one of the first plastic part and the second plastic part is made of PPS and / or PP.

[0027] A second object of the present invention is to provide a top cover assembly structure, comprising a top cover sheet and the lower plastic component as described above, wherein the lower plastic component is arranged at the bottom of the top cover sheet.

[0028] As an improvement of the top cover assembly structure described in the present invention, a liquid injection port is provided on the top cover sheet, and a liquid injection net is provided on the second plastic part. The liquid injection net at least covers the vertical projection surface of the liquid injection port, and the area of ​​the mesh of the liquid injection net is smaller than the area of ​​the liquid injection port.

[0029] As an improvement of the top cover assembly structure described in the present invention, a boss is extended from the lower surface of the liquid injection port, and a protective protrusion is correspondingly provided on the liquid injection net, and the radius of the protective protrusion is greater than the radius of the boss.

[0030] As an improvement of the top cover assembly structure described in the present invention, a plurality of overflow grooves are provided on the protection protrusion.

[0031] As an improvement of the top cover assembly structure described in the present invention, at least one of the top cover sheet and the first plastic part is provided with a hot melt column and / or a hot melt groove, and the top cover sheet and the first plastic part are hot-melted.

[0032] The third object of the present invention is to provide a power battery, comprising a battery cell, a battery shell accommodating the battery cell, and a top cover sheet sealed and mounted on the battery shell, wherein the above-mentioned lower plastic part is arranged between the battery cell and the top cover sheet, and the electrode tab of the battery cell is fixed between the first plastic part and the second plastic part.

[0033] The beneficial effect of the present invention is that the present invention comprises a first plastic part for spacing the battery cell and the top cover sheet; and a second plastic part connected to the first plastic part; wherein the lower plastic part has an installation state and a pre-installation state, wherein when in the installation state, the second plastic part moves to the same direction position as the first plastic part. Since a lug pad is added between the existing battery cell and the top cover, the corresponding manufacturing process and assembly steps are added; on the one hand, the processing and assembly process are more complicated, and it is easy to cause the lug pad to be missed during the assembly process; on the other hand, the error in the manufacturing process of the lug pad and the assembly error between the lug pad and the lower plastic are easy to affect the assembly effect. Therefore, the second plastic part is rotatably connected to the first plastic part, and the second plastic part can be flipped relative to the first plastic part, so that the first plastic part and the second plastic part adopt an integrated design, which is equivalent to a single part, and the lower plastic part has an installation state and a pre-installation state, and the second plastic part 2 moves to the same direction position as the first plastic part 1, not only the assembly error is small, but also it is convenient to install and position the first plastic part and the second plastic part, and the installation of the lug pad is omitted, the assembly steps are simplified, and the situation of missing during the assembly process is avoided, which helps to simplify the production process, thereby reducing the manufacturing cost. The present invention can simplify the assembly steps, help reduce the manufacturing cost, and can also reduce the overall size error and improve the overall assembly effect of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a structural schematic diagram of implementation mode 1 of the present invention.

[0035] Figure 2 It is a schematic structural diagram of implementation mode 1 of the present invention before bending.

[0036] Figure 3 It is a schematic diagram of the structure after bending in the first embodiment of the present invention.

[0037] Figure 4 This is a structural schematic diagram of forming a second plastic part at one end of a first plastic part in implementation mode 6 of the present invention.

[0038] Figure 5 Schematic diagram of the structure of the first plastic part and the second plastic part when they are hinged in Embodiment 8 of the present invention.

[0039] Figure 6 It is a structural schematic diagram of implementation mode 9 of the present invention.

[0040] Figure 7 It is a schematic cross-sectional structure diagram of implementation mode 9 of the present invention.

[0041] Figure 8 for Figure 7 Enlarged view of point A.

[0042] Fig. 9 A schematic diagram of the structure of the tenth embodiment of the present invention

[0043] Among them: 1-first plastic part; 2-second plastic part; 21-liquid injection net; 211-protective protrusion; 2111-overflow groove; 31-clamping part; 32-buckle part; 4-bending part; 5-inclined surface; 6-rounded corner; 7-explosion-proof valve vent; 8-top cover piece; 81-liquid injection port; 811-boss; 9-battery cell; Z-up and down direction; X-left and right direction; Y-front and back direction. DETAILED DESCRIPTION

[0044] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0045] In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "horizontal", etc. are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention.

[0046] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0047] The following is combined with Figures 1 to 9 The present invention is further described in detail, but is not intended to limit the present invention.

[0048] Implementation Method 1

[0049] A lower plastic part for a power battery, comprising:

[0050] The first plastic part 1 is used to separate the battery cell 9 and the top cover sheet 8;

[0051] The second plastic part 2 is connected to the first plastic part 1;

[0052] The lower plastic part has an installation state and a pre-installation state. When in the installation state, the second plastic part 2 moves to a position in the same direction as the first plastic part 1 .

[0053] Since the tab pad is added between the existing battery cell and the top cover, the corresponding manufacturing process and assembly steps are increased; on the one hand, the processing and assembly process are more complicated, and it is easy to cause the tab pad to be missed during the assembly process; on the other hand, the error in the manufacturing process of the tab pad and the assembly error between the tab pad and the lower plastic are easy to affect the assembly effect. Figures 1 to 3 , the second plastic part 2 is rotatably connected to the first plastic part 1, so that the first plastic part 1 and the second plastic part 2 are designed in an integrated manner, equivalent to a single part, and the lower plastic part has an installation state and a pre-installation state, and the second plastic part 2 moves to the same direction position as the first plastic part 1, which not only reduces the assembly error, but also facilitates the installation and positioning of the first plastic part 1 and the second plastic part 2, and eliminates the need to install the tab pad, simplifies the assembly steps, avoids the occurrence of missing assembly during the assembly process, and helps to simplify the production process, thereby reducing manufacturing costs. Among them, the pre-installation state includes but is not limited to the lower plastic part being in an unfolded state, and also includes a state where any angle other than zero degrees can be formed between the first plastic part 1 and the second plastic part 2.

[0054] See also Figures 1 to 3 In this embodiment, the battery has two poles for outputting electric energy to the outside, namely, the first pole and the second pole, both of which are arranged on the top cover sheet 8. The first pole can be a positive pole or a negative pole. Correspondingly, the second pole is a negative pole or a positive pole. The first plastic part 1 is provided with through holes corresponding to the first pole and the second pole of the top cover sheet 8. The battery cell 9 in the battery is connected with a first pole ear and a second pole ear. The first pole ear is connected to the first pole by laser welding, and the second pole ear is connected to the second pole. The positive electrode sheet, the separator and the negative electrode sheet in the battery cell 9 can be stacked and wound in sequence. The positive electrode sheet includes a positive electrode collector and a positive electrode active material coated on the surface of the positive electrode collector. The negative electrode sheet includes a negative electrode collector and a negative electrode active material coated on the surface of the negative electrode collector. The first pole ear is connected to the positive electrode collector, and the second pole ear is connected to the negative electrode collector. The edge of the positive electrode collector may have a blank area not covered by the positive electrode active material. The first pole ear can be directly formed by cutting the blank area. Similarly, the second pole tab can be directly cut through the blank area of ​​the negative electrode current collector. In addition, the first pole tab and the second pole tab can also be fixed to the blank areas of the positive electrode sheet and the negative electrode sheet respectively by welding.

[0055] The first plastic part 1 and the second plastic part 2 are an integrally formed structure, and at least one end of the first plastic part 1 extends outward to form the second plastic part 2. Figures 1 to 3 The two ends of the first plastic part 1 extend outward to form the second plastic part 2. The first plastic part 1 and the second plastic part 2 adopt an integrated molding structure, which can not only improve the overall rigidity of the lower plastic part, but also simplify the manufacturing process, reduce production costs, and help control dimensional errors and improve the positioning accuracy of the first plastic part 1 and the second plastic part 2.

[0056] At least one of the first plastic part 1 and the second plastic part 2 is provided with a clamping part 31 and / or a buckle part 32, and the first plastic part 1 is connected with the second plastic part 2 by a buckle. Specifically, the second plastic part 2 is provided with a buckle part 32, and the first plastic part 1 is provided with a clamping part 31. The buckle part 32 cooperates with the clamping part 31 to fix the second plastic part 2 to the first plastic part 1, and does not occupy the internal space of the battery, thereby reserving more space for the electrode assembly and improving the energy density of the battery; the radius of the buckle part 32 is greater than the radius of the clamping part 31, so that the buckle part 32 is convenient for fixing in the clamping part 31, and the buckle part 32 can be designed to include two half-tenons separated in the middle, and there is a certain gap between the two half-tenons, so that when the buckle part 32 is inserted into the clamping part 31, the two half-tenons extend and retract toward each other, so as to facilitate insertion into the clamping part 31. The buckle 32 can also be set to other shapes with thin ends and thicker in the middle, which can be fixed to the clamping part 31, but the present invention is not limited to this. The first plastic part 1 can be provided with a buckle 32, and the second plastic part 2 can be provided with a clamping part 31. In addition, the first plastic part 1 can be provided with a buckle 32 and a clamping part 31, and correspondingly, the second plastic part 2 is provided with a clamping part 31 and a buckle 32, so as to improve the stability between the first plastic part 1 and the second plastic part 2, so as to achieve the effect of maintaining the relative position relationship between the first plastic part 1 and the second plastic part 2 after assembly, and improving the stability of battery assembly. However, the present invention is not limited to this, because when assembling batteries, the arrangement of the various components in the shell of batteries of different models or sizes will also be different. The second plastic part 2 is turned over and fixedly connected with the first plastic part 1, and the fixed connection method also includes bonding, thermal welding and ultrasonic connection.

[0057] A bending portion 4 is provided between the first plastic part 1 and the second plastic part 2. The second plastic part 2 can be folded toward the first plastic part 1 along the bending portion 4. The bending portion 4 is completely disconnected or connected at least at one place after the second plastic part 2 is folded. The bending portion 4 is added so that the first plastic part 1 and the second plastic part 2 can be bent at the bending portion 4. According to actual production requirements, the structure of the bending portion 4 can be designed to be partially disconnected after bending, which is convenient for positioning and connecting the first plastic part 1 and the second plastic part 2. The structure of the bending portion 4 can also be designed to be completely disconnected after bending, which can reduce the accumulation of dimensional tolerances and prevent deformation of the lower plastic part.

[0058] The second plastic part 2 is provided with an upwardly inclined inclined surface 5 along the front and rear side edges, and the inclined surface 5 is a plane or a downward convex curved surface. Specifically, the second plastic part 2 is provided with an upwardly inclined inclined surface 5 along the front and rear side edges Y, which can further avoid the tabs of the battery cell 9 from being crushed during the assembly process, and the inclined surface 5 is a plane or a downward convex curved surface, preferably a downward convex curved surface, which can avoid the tabs from bending at the corners of the second plastic part 2 to cause stress concentration, or the sharp corners of the edges piercing the pole piece. In addition, the inclined surface 5 can reduce the wear on the tabs of the battery cell 9, further improve the performance of the secondary battery, and extend the service life of the secondary battery.

[0059] The upper and lower edges of the slopes on both sides of the second plastic part 2 are provided with rounded corners 6. Specifically, along the up-down direction Z, the upper and lower edges of the slopes on both sides of the second plastic part 2 are provided with rounded corners 6, which can reduce the pressure on the pole piece during assembly, avoid stress concentration, sharp edges piercing the pole piece, etc.

[0060] The first plastic part 1 is provided with an explosion-proof valve vent 7 corresponding to the explosion-proof valve, and / or the second plastic part 2 is provided with an explosion-proof valve vent 7 corresponding to the explosion-proof valve. The explosion-proof valve can automatically and quickly release pressure from the battery when the internal pressure of the battery rises due to overcharging, overdischarging, overcurrent and internal short circuit of the battery, so as to avoid the occurrence of safety accidents caused by battery explosion. The explosion-proof valve vent 7 can ensure that the internal pressure of the battery can be released through the explosion-proof valve in time, and ensure that the explosion-proof valve can be used normally. The explosion-proof valve vent 7 includes but is not limited to being set in the first plastic part 1 or the second plastic part 2. The explosion-proof valve vent 7 can be set at the positions corresponding to the explosion-proof valve of the first plastic part 1 and the second plastic part 2, so that the gas generated in the battery can easily reach the explosion-proof valve, reducing the probability of danger. The shape of the explosion-proof valve vent 7 can be circular or elliptical. In addition, the first plastic part 1 can also be provided with a liquid injection through hole matching the liquid injection port 81 to ensure the liquid injection efficiency. The explosion-proof valve air holes 7 can be composed of holes of various shapes such as triangular holes, circular holes, square holes, etc. A plurality of holes can be arranged according to certain rules to form a gas channel. Preferably, a plurality of circular holes are used. When thermal runaway occurs in the secondary battery, it can not only ensure ventilation, but also prevent high-temperature fixed particles from passing through the mesh holes, thereby preventing other flammable and high-temperature solid particles from being ejected out of the explosion-proof valve and mixed with air to burn, thereby significantly improving the battery safety performance.

[0061] After the battery is assembled, the battery cell 9 in the battery is prone to shaking during use. For example, during the use of the battery used in an electric vehicle, the battery cell 9 in the battery is prone to shaking due to the shaking of the car during travel. In order to solve this problem, the ratio of the contact area between the second plastic part 2 and the top surface of the battery cell 9 to the total area of ​​the top surface of the battery cell 9 is set to be greater than 50%. The side of the second plastic part 2 that contacts the top surface of the battery cell 9 is a planar structure. If the contact area between the second plastic part 2 and the top surface of the battery cell 9 is too small, it is easy to cause the battery cell 9 to shake. The contact part between the second plastic part 2 and the top surface of the battery cell 9 can limit the battery cell 9, thereby reducing the battery cell 9 in the battery from shaking easily. Therefore, the ratio of the contact area between the second plastic part 2 and the top surface of the battery cell 9 to the total area of ​​the top surface of the battery cell 9 is greater than 50%, preferably 60%, 65%, 70%, 75%, 80%, 85% and above.

[0062] At least one of the first plastic part 1 and the second plastic part 2 is made of PPS and / or PP. The first plastic part 1 and the second plastic part 2 are made of different materials. Specifically, the first plastic part 1 is made of PPS material, and the second plastic part 2 is made of PP material. The first plastic part 1 can also be made of PP material, and the second plastic part 2 can be made of PPS material, to prevent the plastic parts from being easily bent and deformed when the same material is used.

[0063] Implementation Method 2

[0064] The difference from the first embodiment is that the first plastic part 1 of this embodiment extends outwards at any point between its two ends to form the second plastic part 2. Any point between the two ends of the first plastic part 1 can extend outwards to form the second plastic part 2, and the second plastic part 2 can be rotatably connected to the first plastic part 1.

[0065] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0066] Implementation Method 3

[0067] The difference from the first embodiment is that at least one of the first plastic part 1 and the second plastic part 2 of this embodiment is provided with an adhesive layer and / or an adhesive surface, and the first plastic part 1 is bonded to the second plastic part 2. Specifically, an adhesive layer, an adhesive layer or other viscous material is provided on the first plastic part 1 or the second plastic part 2 on the contact surface after the first plastic part 1 and the second plastic part 2 are folded, and the first plastic part 1 and the second plastic part 2 are fixed together by bonding, so that the relative position relationship between the first plastic part 1 and the second plastic part 2 is maintained after assembly, thereby improving the stability of battery assembly.

[0068] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0069] Implementation Method 4

[0070] Different from the first embodiment, at least one of the first plastic part 1 and the second plastic part 2 of this embodiment is provided with a hot melt column and / or a hot melt groove, and the first plastic part 1 is hot-melted to the second plastic part 2. Specifically, at least one hot melt column is provided on the first plastic part 1 or the second plastic part 2, and a hot melt groove is provided at a corresponding position of the first plastic part 1 or the second plastic part 2. The first plastic part 1 and the second plastic part are fixed together by hot-melt connection, so that after assembly, the relative position relationship between the first plastic part 1 and the second plastic part 2 is maintained, the stability of the battery assembly is improved, and the internal space of the battery is not occupied, thereby reserving more space for the electrode assembly and improving the energy density of the battery.

[0071] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0072] Implementation Method 5

[0073] The difference from the first embodiment is that the thickness of the bending portion 4 of this embodiment is less than the thickness of the first plastic part 1 or the thickness of the second plastic part 2, and the bending portion 4 is provided with at least one of a fracture line, a disconnection groove and a disconnection hole, and the bending portion 4 is connected or disconnected after the second plastic part 2 is folded. Since the thickness of the bending portion 4 is smaller, it can be bent more easily. Preferably, the thickness of the bending portion 4 is 2-5 mm, and the bending portion 4 can also be disconnected by providing a fracture line, a disconnection groove and a disconnection hole. When the bending portion 4 is disconnected, at least a part of the bending portion 4 is not disconnected, that is, the second plastic part 2 is not completely disconnected after bending; in addition, the thickness of the bending portion 4 is less than the thickness of the first plastic part 1 or the thickness of the second plastic part 2, and the bending portion 4 can also be disconnected.

[0074] Alternatively, the bending portion 4 may be configured to be breakable, that is, the second plastic part 2 is bent toward the first plastic part 1 and then broken, thereby avoiding deformation of the second plastic part 2 after the first plastic part 1 and the second plastic part 2 are fixed due to error accumulation between the two parts.

[0075] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0076] Implementation Method 6

[0077] The difference from the first implementation mode is: Figure 4 One end of the first plastic part 1 extends outward to form a second plastic part 2. When assembling the battery, only one second plastic part 2 needs to be bent toward the first plastic part 1, eliminating the step of bending another second plastic part 2, which helps to simplify the production process and thus improve production efficiency.

[0078] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0079] Implementation Method 7

[0080] The difference from the first embodiment is that the first plastic part 1 of this embodiment is broken into two parts along the middle, and at least one end of each part extends outward to form the second plastic part 2. Specifically, the first plastic part 1 is broken into two parts along the middle, that is, the first plastic part 1 is divided into left and right parts along the left-right direction X, and is separated at the explosion-proof valve. The first plastic part 1 of the left part extends on the side close to the explosion-proof valve to form the second plastic part 2, or extends away from the side of the explosion-proof valve to form the second plastic part 2. At the same time, the first plastic part 1 of the right part can also form the second plastic part 2 according to this structure; the first plastic part 1 is broken into two parts along the middle, so that the first plastic part 1 and the second plastic part 2 do not block the explosion-proof valve, so there is no need to set the explosion-proof valve vent 7 on the first plastic part 1 and the second plastic part 2. In addition, after the first plastic part 1 is divided into two parts, it can avoid the accumulation of errors between the first plastic part 1 and the second plastic part 2, which causes the second plastic part 2 to deform after the two are fixed.

[0081] The other structures are the same as those in the first embodiment and will not be described in detail here.

[0082] Implementation Method 8

[0083] In order to achieve a better assembly effect between the first plastic part 1 and the second plastic part 2, one end of the first plastic part 1 and the second plastic part 2 are hinged, riveted or ultrasonically connected. Figure 5 , one end of the first plastic part 1 is hinged to the second plastic part 2, that is, the first plastic part 1 and the second plastic part 2 are rotatably connected via a rotating shaft, the rotating shaft can be set separately, the first plastic part 1 and the second plastic part 2 are both provided with a rotating shaft hole, the rotating shaft can also be integrally set at the end of the first plastic part 1 or the second plastic part 2, the corresponding end of the first plastic part 1 or the second plastic part 2 is provided with a rotating shaft hole, which satisfies the rotation connection between the two, and helps to achieve a better rotation connection between the first plastic part 1 and the second plastic part 2, not only reducing the resistance during the rotation process, The probability of the second plastic part 2 rebounding during use is also reduced. The first plastic part 1 and one end of the second plastic part 2 can also be ultrasonically connected. Specifically, the two are ultrasonically heat-fused into one piece in the middle. When the heat-fused part is bent, the strength of the heat-fused part is relatively low and it is easier to bend, which is equivalent to a smaller thickness at the connection between the two. That is, the second plastic part 2 is bent toward the first plastic part 1 and then disconnected. This can avoid the accumulation of errors between the first plastic part 1 and the second plastic part 2, which may cause the second plastic part 2 to deform after the two are fixed.

[0084] Implementation Method 9

[0085] A top cover assembly structure includes a top cover sheet 8 and a lower plastic component as in Embodiments 1 to 6, wherein the lower plastic component is arranged at the bottom of the top cover sheet 8.

[0086] It should be noted that: See Figure 6 The battery has two poles for outputting electric energy to the outside, namely, a first pole and a second pole, both of which are arranged on the top cover sheet 8. The first pole can be a positive pole or a negative pole, and correspondingly, the second pole is a negative pole or a positive pole. The first plastic part 1 is provided with through holes corresponding to the first pole and the second pole of the top cover sheet 8. The first plastic part 1 and the second plastic part 2 play the role of insulating the top cover sheet 8 and the battery cell 9, and can also prevent the electrolyte from corroding the top cover sheet 8, which helps to extend the service life of the battery.

[0087] Reference Figures 6 to 8 The top cover sheet 8 is provided with a liquid injection port 81, and the second plastic part 2 is provided with a liquid injection net 21. The liquid injection net 21 at least covers the vertical projection surface of the liquid injection port 81, and the mesh area of ​​the liquid injection net 21 is smaller than the area of ​​the liquid injection port 81. The liquid injection net 21 is provided with a plurality of meshes, and the mesh size is smaller than the size of the liquid injection port 81. The liquid injection net 21 can prevent the plastic nails of the liquid injection port 81 from falling into the battery cell 9 from the liquid injection port 81 during the formation process. The liquid injection net 21 at least completely covers the projection surface range below the liquid injection port 81. In addition, the first plastic part 1 is provided with a liquid injection through hole matching the liquid injection port 81, and the liquid injection through hole is located directly above the liquid injection net 21.

[0088] The mesh holes in the liquid injection net 21 can be composed of holes of various shapes such as triangular holes, circular holes, square holes, etc. A plurality of holes can be arranged according to certain rules to form a gas channel, and preferably a plurality of circular holes are used.

[0089] Reference Figure 8 A boss 811 extends from the lower surface of the injection port 81, and a protective protrusion 211 is correspondingly provided on the injection net 21, and the radius of the protective protrusion 211 is greater than the radius of the boss 811. A boss 811 extends from the lower side of the injection port 81, and the second plastic part 2 is provided with a protective protrusion 211 corresponding to the boss 811, and the radius of the protective protrusion 211 is greater than the radius of the boss 811. The protective protrusion 211 cooperates with the boss 811 to prevent the chemical nail from falling from the injection port 81 into the gap between the first plastic part 1 and the second plastic part 2, wherein the boss 811 can be formed by stamping the lower surface of the top cover sheet 8.

[0090] Reference Figure 6 , a plurality of overflow grooves 2111 are provided on the protective protrusion 211. In order to ensure the injection efficiency and prevent the injection port 81 from being blocked, a plurality of overflow grooves 2111 are provided on the protective protrusion 211. The overflow grooves 2111 ensure that after the second plastic part 2 is fixed to the first plastic part 1, no closed flow channel is formed between the protective protrusion 211 and the boss 811, and the electrolyte can flow from the overflow grooves 2111 to the outside of the protective protrusion 211, thereby ensuring the injection efficiency.

[0091] At least one of the top cover sheet 8 and the first plastic part 1 is provided with a hot melt column and / or a hot melt groove, and the top cover sheet 8 and the first plastic part 1 are hot-melted. Specifically, at least one hot melt column is provided on the top cover sheet 8 or the first plastic part 1, and a hot melt groove is provided at a corresponding position of the top cover sheet 8 or the first plastic part 1. The top cover sheet 8 and the first plastic part 1 are fixed together by hot-melt connection, which helps to prevent the plastic from warping and improve the stability between the top cover sheet 8 and the first plastic part 1. It will not occupy the internal space of the battery, thereby reserving more space for the electrode assembly and improving the energy density of the battery.

[0092] Implementation Method 10

[0093] Reference Fig. 9 A power battery includes a battery cell 9, a battery shell accommodating the battery cell 9, and a top cover sheet 8 sealed and mounted on the battery shell. A lower plastic part of embodiments 1 to 6 is arranged between the battery cell 9 and the top cover sheet 8, and a pole ear of the battery cell 9 is fixed between a first plastic part 1 and a second plastic part 2.

[0094] The top cover sheet 8 is provided with mounting holes corresponding to the first pole and the second pole, the first pole and the second pole are provided with sealing members, and the first plastic part 1 is provided with through holes corresponding to the first pole and the second pole of the top cover sheet 8, the sealing member and the first plastic part 1 both play the role of insulating the top cover sheet 8 and the pole, the battery cell 9 in the battery is connected with the first pole ear and the second pole ear, the first pole ear is connected with the first pole column by laser welding, and the second pole ear is connected with the second pole column, wherein the positive electrode sheet, the separator and the negative electrode sheet in the battery cell 9 can be stacked and wound in sequence, the positive electrode sheet includes a positive electrode collector and a positive electrode active material coated on the surface of the positive electrode collector, and the negative electrode sheet includes a negative electrode collector and a negative electrode active material coated on the surface of the negative electrode collector. The first pole ear is connected to the positive electrode collector, the second pole ear is connected to the negative electrode collector, the edge of the positive electrode collector may have a blank area not covered by the positive electrode active material, and the first pole ear can be directly formed by cutting the blank area. Similarly, the second pole tab can be directly cut through the blank area of ​​the negative electrode current collector. In addition, the first pole tab and the second pole tab can also be fixed to the blank areas of the positive electrode sheet and the negative electrode sheet respectively by welding.

[0095] When there are a large number of cells 9 in the battery or the tabs are short, an adapter is used during assembly, and the adapter includes a first adapter and a second adapter. The first tab is connected to the first pole through the first adapter. The second tab is connected to the second pole through the second adapter, thereby improving the orderly connection inside the battery.

[0096] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs can also change and modify the above embodiment. Therefore, the present invention is not limited to the above specific embodiment, and any obvious improvement, replacement or modification made by those skilled in the art on the basis of the present invention belongs to the protection scope of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention.

Claims

1. A lower plastic part for a power battery, characterized in that: include: A first plastic part (1), used for spacing the battery cell (9) and the battery top cover (8); A second plastic part (2) is foldably connected to the first plastic part (1); The lower plastic part has an installation state and a pre-installation state. When in the installation state, the second plastic part (2) is folded to the same direction as the first plastic part (1), and the second plastic part (2) is located between the first plastic part (1) and the battery cell (9). The pre-installation state is a state in which the lower plastic part is in an unfolded state, or a state in which any angle other than zero degree is formed between the first plastic part (1) and the second plastic part (2). Along the length direction of the first plastic part (1), at least one end portion of the first plastic part (1) extends outwards to form the second plastic part (2).

2. A lower plastic part for a power battery as claimed in claim 1, characterized in that: The first plastic part (1) is hinged, riveted or ultrasonically welded to one end of the second plastic part (2), and the other end of the second plastic part (2) is flipped over and fixedly connected to the first plastic part (1), wherein the fixed connection method includes at least one of the following: snap connection, bonding, heat welding and ultrasonic welding.

3. A lower plastic part for a power battery as claimed in claim 1, characterized in that: A bending portion (4) is provided between the first plastic part (1) and the second plastic part (2); the second plastic part (2) can be folded along the bending portion (4) toward the first plastic part (1); and the bending portion (4) is completely disconnected or connected at least at one point after the second plastic part (2) is folded.

4. A lower plastic part for a power battery as claimed in claim 1, characterized in that: The second plastic part (2) is provided with inclined surfaces (5) along the side edges of the second plastic part (2) in the width direction thereof, the inclined surfaces (5) being inclined in a direction away from the first plastic part (1); the inclined surfaces (5) are plane surfaces or downwardly convex curved surfaces.

5. The lower plastic part for a power battery according to claim 1, characterized in that: The first plastic part (1) is broken into two parts along the middle, and at least one end of each part extends outward to form the second plastic part (2).

6. A lower plastic part for a power battery as claimed in claim 1, characterized in that: The ratio of the contact area between the second plastic part (2) and the top surface of the battery cell (9) to the total area of ​​the top surface of the battery cell (9) is greater than 50%.

7. The lower plastic part for a power battery according to claim 1, characterized in that: The material of at least one of the first plastic part (1) and the second plastic part (2) is PPS and / or PP.

8. A top cover assembly structure, characterized in that: The invention comprises a top cover sheet (8) and a lower plastic part as claimed in any one of claims 1 to 7, wherein the lower plastic part is arranged at the bottom of the top cover sheet (8), the top cover sheet (8) is provided with a liquid injection port (81), the second plastic part (2) is provided with a liquid injection net (21), a boss (811) extends from the lower surface of the liquid injection port (81), the liquid injection net (21) is correspondingly provided with a protective protrusion (211), and the protective protrusion (211) is provided with a plurality of overflow grooves (2111).

9. A power battery, comprising a battery cell (9), a battery housing for accommodating the battery cell (9), and a top cover sheet (8) sealed and mounted on the battery housing, characterized in that: A lower plastic part according to any one of claims 1 to 7 is arranged between the battery cell (9) and the top cover sheet (8), and a tab of the battery cell (9) is fixed between the first plastic part (1) and the second plastic part (2).

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