Cover plate assembly and battery cell

Abstract

The utility model relates to battery technical field discloses the cover plate subassembly and electric core. Cover plate subassembly includes: cover plate body and first plastic piece. First plastic piece includes the main part, the bent part and the fixed part that connect in proper order, and the fixed part can be folded around the bent part, so that the fixed part can switch between the free state and the fixed state, when the fixed part is in the free state, provide the room for the welding of the pole lug and the pole column, when the pole lug and the pole column weld, the fixed part switches to the fixed state, and the positioning column is inserted into the positioning hole after passing through the first through -hole, realize the fixed connection of first plastic piece and cover plate body, the pole lug is clamped between the fixed part and the main part, the fixed part presses the pole lug on the pole column, and the pole lug is always fixed between the fixed part and the main part and does not produce the deformation by the compaction effect of the fixed part, play the role of fixing and shaping the pole lug, and the free end part of the pole lug is separated from the pole group by the fixed part, avoid the pole lug to insert into the pole group, reduce the probability that the electric core takes place short circuit.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a cover plate assembly and a battery cell. Background Technology

[0002] A cover plate assembly typically includes a cover plate body, terminal posts, upper plastic, and lower plastic components. The cover plate body is welded to the battery cell casing to form a sealed space accommodating the electrode assembly. The terminal posts are integrated onto the cover plate body and are welded to the electrode tabs of the electrode assembly. The upper plastic is located on the side of the cover plate body facing outwards from the casing and between the cover plate body and the terminal posts to ensure insulation between the terminal posts and the cover plate body. The lower plastic is located on the side of the cover plate body facing inwards from the casing cavity to ensure insulation between the cover plate body and the electrode assembly.

[0003] However, since the electrode assembly is composed of several electrode sheets stacked together, the corresponding electrode tabs include several layers of stacked metal foils. After the tabs are welded to the electrode post, the electrode tabs are relatively dispersed, and the tabs are very easy to be inserted into the electrode assembly backwards, causing a short circuit in the electrode assembly and affecting the safety and performance of the product. Utility Model Content

[0004] In view of this, the present invention provides a cover plate assembly and a battery cell to solve the problem that the electrode tabs are relatively scattered and easily cause short circuits in the electrode group.

[0005] In a first aspect, this utility model provides a cover plate assembly, comprising: a cover plate body having a first surface formed on a first side along the Z direction, the cover plate body having an electrode through hole and a positioning hole, the positioning hole being constructed on the first surface; an electrode, passing through the electrode through hole and adapted to be welded to an electrode lug; a first plastic part, comprising a main body, a fixing part, and a bending part, the main body being disposed on the first side of the cover plate body, the main body having a first through hole corresponding to the positioning hole and a second through hole corresponding to the electrode through hole, the bending part being connected between the main body and the fixing part, the fixing part being foldable relative to the main body around the bending part, the fixing part having a free state of folding relative to the main body and a fixed state of being fastened to the main body; a positioning post being provided on the fixing part, the positioning post passing through the first through hole and cooperating with the positioning hole when the fixing part is in the fixed state, the fixing part and the main body being adapted to clamp an electrode lug.

[0006] Beneficial effects: By setting the first plastic part to include a main body, a bending part, and a fixing part connected in sequence, and the fixing part can be folded around the bending part, the fixing part can switch between a free state and a fixed state. When the fixing part is in the free state, it provides space for welding the tab and the pole, making it easier to weld the tab and the pole. After the tab and the pole are welded, the fixing part switches to the fixed state, and the positioning post passes through the first through hole and is inserted into the positioning hole, realizing the fixed connection between the first plastic part and the cover plate body. The fixing part covers the tab, and the fixing part clamps the tab between the fixing part and the main body. The fixing part presses the tab tightly onto the pole. Relying on the compaction of the fixing part, the tab is always fixed between the fixing part and the main body without deformation, playing the role of fixing and shaping the tab, ensuring that the shape of the tab remains unchanged. The fixing part also separates the free end of the tab from the pole group, preventing the tab from being inserted backward into the pole group, reducing the probability of short circuit in the cell, and improving the safety performance of the cell.

[0007] In one optional embodiment, the positioning hole is a blind hole, and the area of ​​the bottom surface of the positioning hole is larger than the area of ​​the opening of the positioning hole; the positioning post includes a post portion and a head portion, at least a portion of the post portion is inserted into the first through hole, and the head portion is located in the positioning hole and cooperates with the positioning hole.

[0008] Beneficial effects: By designing the positioning hole as a blind hole, and ensuring that the bottom area of ​​the positioning hole is larger than its opening area, the head of the positioning post can be engaged in the positioning hole, achieving a snap-fit ​​between the positioning post and the positioning hole. This securely connects the fixing part to the cover plate body. The snap-fit ​​design makes it difficult for the positioning post to come out of the positioning hole. Furthermore, after the positioning post and positioning hole are engaged, the fixing part presses the main body against the cover plate body, further ensuring the relative stability of the first plastic part and the cover plate body. Moreover, by designing the positioning hole as a blind hole, compared to a through hole, not only is damage to the structural strength of the cover plate body reduced, but damage to the sealing performance of the cover plate body is also avoided, thus ensuring the reliability of the cover plate body.

[0009] In one alternative implementation, the positioning post is fitted with the positioning hole by heat fusion.

[0010] Beneficial effects: The hot-melt method requires no additional connectors, has a simple structure, is easy to operate, can reduce costs, and has high connection strength, stable structure, and long-term reliability.

[0011] In one optional embodiment, the dimension of the column portion along the X and / or Y directions is d, and the dimension of the first through hole along the X and / or Y directions is D, wherein D is greater than d.

[0012] Beneficial effects: It ensures that the positioning post can pass smoothly through the first through hole, thereby ensuring that the positioning post can be easily inserted into the positioning hole, thus ensuring the process yield.

[0013] In one optional embodiment, the dimension d of the column along the X and / or Y directions ranges from 1.5mm to d to 3.5mm.

[0014] And / or, the dimension D of the first through hole along the X direction and / or Y direction is in the range of 1.8mm≤D≤3.8mm.

[0015] Beneficial effects: By limiting d to a value within the range of 1.5mm to 3.5mm, the structural strength of the positioning post and the reliability of the connection between the fixing part and the cover plate body can be guaranteed, thereby improving the safety of the battery cell. At the same time, material waste can be avoided, thus saving costs.

[0016] And / or, by limiting D to a value between 1.8mm and 3.8mm, it is possible to ensure the smooth processing and forming of the first through hole and the smooth passage of the positioning post, thus ensuring the process yield. It is also possible to ensure the tightness of the fit between the positioning post and the first through hole, thereby ensuring the relative stability between the fixing part and the main body and improving the reliability of the cover plate assembly.

[0017] In one optional embodiment, the main body includes a plastic body and a protruding structure. The protruding structure is connected to the side of the plastic body away from the cover plate body. When the fixing part is in the fixed state, the side of the protruding structure away from the plastic body abuts against the side of the fixing part facing the main body.

[0018] Beneficial effects: By constructing a protruding structure on the main body, when the fixing part is in a fixed state, the protruding structure supports the plastic body and the fixing part, so that there is a stable gap space between the plastic body and the fixing part, thereby providing a space for the electrode tab, avoiding excessive pressure damage to the electrode tab, and thus ensuring the reliability of the battery cell.

[0019] In one alternative embodiment, the first through hole extends through the protruding structure and the plastic body along the Z direction.

[0020] Beneficial effects: By setting a first through hole that penetrates the protruding structure and the plastic body along the Z direction, not only is the dimension of the first through hole along the Z direction increased, improving the stability of the structure after the first through hole is opened in the main body, but the protruding structure also surrounds the outer periphery of the positioning post, further improving the stability of the positioning post, thereby improving the reliability of the cover plate assembly.

[0021] In one optional embodiment, the dimension of the first through hole along the Z direction is H1, wherein the value of H1 is in the range of 0.8mm≤H1≤3.2mm;

[0022] And / or, the dimension of the plastic part body along the Z direction is h, wherein the value of h is in the range of: 0.45mm≤h≤1.2mm;

[0023] And / or, when the fixing part is in the fixed state, the plastic body and the fixing part are parallel to each other.

[0024] Beneficial effects: By limiting H1 to a value within the range of 0.8mm to 3.2mm, it can ensure that there is enough space between the fixing part and the main body to accommodate the electrode tab, avoiding damage to the electrode tab, and also ensure the compaction of the fixing part on the electrode tab, preventing the electrode tab from loosening or moving, avoiding damage to the electrode tab, thereby ensuring the overcurrent capacity of the battery cell.

[0025] And / or, by limiting h to a value between 0.45mm and 1.2mm, it is possible to ensure that the plastic part body has sufficient structural strength and structural stability, thereby improving the reliability of the cover plate assembly, while avoiding material waste, saving costs, and avoiding excessive weight of the plastic part body, reducing the space occupied by the plastic part body inside the cell, which is conducive to improving the energy density of the cell.

[0026] And / or, by setting the fixing part to be parallel to the plastic body when in the fixed state, the plastic body and the fixing part are equally spaced, so that the fixing part has the same compaction effect on the tabs at different positions, avoiding local damage or loosening of the tabs, thereby improving the stability of the tabs and ensuring the flow capacity.

[0027] In one alternative embodiment, the dimension of the bent portion along the Y direction is smaller than the dimension of the main body portion along the Y direction;

[0028] And / or, the cover plate body is provided with an explosion-proof valve hole, the main body is provided with a third through hole corresponding to the explosion-proof valve hole, the fixing part is provided with a venting area corresponding to the third through hole, and the venting area is provided with a venting hole.

[0029] Beneficial effects: By setting the dimension of the bending part along the Y direction to be smaller than that of the main body along the Y direction, the structural strength of the bending part is less than that of the main body and the fixing part, which makes it easier to bend the first plastic part from the bending part, reduces the difficulty of operation, and helps to improve work efficiency.

[0030] And / or, by opening an explosion-proof valve hole on the cover plate body, and providing a third through hole and a vent hole corresponding to the explosion-proof valve hole on the main body and fixing part of the first plastic part respectively, the first plastic part is prevented from blocking the explosion-proof valve hole, so that when the battery cell experiences thermal runaway, the gas inside the battery cell can be discharged to the outside of the battery cell in sequence through the vent hole, the third through hole and the explosion-proof valve hole, ensuring smooth exhaust and improving the safety performance of the battery cell.

[0031] Secondly, this utility model also provides a battery cell, comprising: a housing having an open end; an electrode assembly located in the inner cavity of the housing, the electrode assembly having electrode tabs; and a cover plate assembly covering the open end of the housing, wherein the electrode post in the cover plate assembly is welded to the electrode tab, and the electrode tab is located between the main body and the fixing part of the first plastic part. Since the battery cell includes a cover plate assembly and has the same effect as the cover plate assembly, it will not be described in detail here. Attached Figure Description

[0032] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a first plastic part according to an embodiment of the present utility model;

[0034] Figure 2 for Figure 1 A structural schematic diagram of the first plastic part from its bottom view;

[0035] Figure 3 for Figure 2 A magnified view of part A in the diagram;

[0036] Figure 4 for Figure 1 A top view of the first plastic part shown;

[0037] Figure 5 for Figure 4 Cross-sectional view along the BB direction;

[0038] Figure 6 for Figure 5 A magnified view of part of C;

[0039] Figure 7 for Figure 5 A magnified view of part of E in the diagram;

[0040] Figure 8 This is a schematic diagram of the structure of a first plastic part and a cover plate body after assembly, with the fixing part in a free state, according to an embodiment of the present utility model.

[0041] Figure 9 for Figure 8 A bottom view structural diagram of the structure after the first plastic part and the cover plate body are assembled.

[0042] Figure 10 for Figure 8 A top view of the structure after the first plastic part and the cover plate body are assembled;

[0043] Figure 11 for Figure 10 A cross-sectional view along the FF direction;

[0044] Figure 12 for Figure 11 A magnified view of a portion of G;

[0045] Figure 13 for Figure 8 The front view of the structure after the first plastic part and the cover plate body are assembled;

[0046] Figure 14 This is a schematic diagram of an assembly structure of a cover plate assembly and an electrode assembly according to an embodiment of the present utility model, wherein the fixing part is in a free state.

[0047] Figure 15 for Figure 14 The front view of the assembly structure shown;

[0048] Figure 16 for Figure 15 A cross-sectional view along the JJ direction;

[0049] Figure 17 for Figure 16 A magnified view of a portion of K;

[0050] Figure 18 This is a schematic diagram of an assembly structure of a cover plate assembly and an electrode assembly after assembly, with the fixing part in a fixed state, according to an embodiment of the present utility model.

[0051] Figure 19 for Figure 18 The front view of the assembly structure shown;

[0052] Figure 20 for Figure 19 A cross-sectional view along the NN direction;

[0053] Figure 21 for Figure 19 Cross-sectional view along the MM direction;

[0054] Figure 22 for Figure 21 A magnified view of a portion of L;

[0055] Figure 23 for Figure 18 The diagram shows the internal structure formed by bending the tabs in the assembly structure.

[0056] Figure 24 for Figure 23 The front view of the shell structure shown;

[0057] Figure 25 for Figure 23 The top view of the shell structure shown;

[0058] Figure 26 for Figure 25 A cross-sectional view along the VV direction;

[0059] Figure 27 for Figure 26 A magnified view of a portion of P;

[0060] Figure 28 for Figure 26 A magnified view of a portion of Q;

[0061] Figure 29 for Figure 25 A cross-sectional view along the U-U direction;

[0062] Figure 30 for Figure 29 A magnified view of a portion of the part near the cover plate assembly.

[0063] Explanation of reference numerals in the attached figures:

[0064] 1. Cover plate body; 101. Positioning hole; 1011. Bottom surface; 110. First surface; 2. First plastic part; 201. First through hole; 202. Second through hole; 203. Third through hole; 210. Main body; 211. Plastic part body; 212. Protruding structure; 220. Fixing part; 221. Positioning post; 2211. Post part; 2212. Head; 222. Vent area; 223. Vent hole; 230. Bending part; 3. Electrode assembly; 301. Electrode lug; 4. Electrode post; 5. Explosion-proof valve. Detailed Implementation

[0065] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0066] A cover plate assembly typically includes a cover plate body, terminal posts, upper plastic, and lower plastic components. The cover plate body is welded to the battery cell casing to form a sealed space accommodating the electrode assembly. The terminal posts are integrated onto the cover plate body and are welded to the electrode tabs of the electrode assembly. The upper plastic is located on the side of the cover plate body facing outwards from the casing and between the cover plate body and the terminal posts to ensure insulation between the terminal posts and the cover plate body. The lower plastic is located on the side of the cover plate body facing inwards from the casing cavity to ensure insulation between the cover plate body and the electrode assembly.

[0067] However, since the electrode assembly is composed of several electrode sheets stacked together, the corresponding electrode tabs include several layers of stacked metal foils. After the tabs are welded to the electrode posts, the shapes of the metal foils in each layer of the electrode tabs are different and relatively dispersed. The tabs are very easy to be inserted into the electrode assembly backwards, causing a short circuit in the electrode assembly and affecting the safety and performance of the product.

[0068] The following is combined Figures 1 to 30 The following describes embodiments of the present invention.

[0069] According to an embodiment of the present invention, a cover plate assembly is provided, comprising: a cover plate body 1 and a first plastic part 2. The cover plate body 1 has a first surface 110 formed on a first side along the Z direction. The cover plate body 1 has a through hole for an electrode post and a positioning hole 101, the positioning hole 101 being constructed on the first surface 110. An electrode post 4 is inserted into the through hole for welding to an electrode lug 301. The first plastic part 2 includes a main body 210, a fixing part 220, and a bending part 230. The main body 210 is disposed on the first side of the cover plate body 1, and has a first through hole 201 corresponding to the positioning hole 101 and a second through hole 202 corresponding to the through hole for the electrode post. The bending portion 230 is connected between the main body portion 210 and the fixing portion 220. The fixing portion 220 can be folded relative to the main body portion 210 around the bending portion 230. The fixing portion 220 has a free state of folding relative to the main body portion 210 and a fixed state of being fastened to the main body portion 210. A positioning post 221 is provided on the fixing portion 220. When the fixing portion 220 is in the fixed state, the positioning post 221 passes through the first through hole 201 and cooperates with the positioning hole 101. The electrode tab 301 is suitable for clamping between the fixing portion 220 and the main body portion 210.

[0070] It should be noted that the cover plate body 1 has a first side and a second side arranged opposite to each other along the Z direction. When the cover plate body 1 is assembled with the housing, the first side of the cover plate body 1 faces the inner cavity of the housing and the second side faces the outside of the housing. The first plastic part 2 is located between the cover plate body 1 and the body of the electrode group 3 to ensure the insulation between the cover plate body 1 and the body of the electrode group. The Z direction is the thickness direction of the cover plate body 1, and the electrode post through hole penetrates the cover plate body 1 along the Z direction.

[0071] The cover plate assembly of this embodiment, by setting the first plastic part 2 to include a main body part 210, a bending part 230 and a fixing part 220 connected in sequence, and the fixing part 220 can be folded around the bending part 230, so that the fixing part 220 can switch between a free state and a fixed state. When the fixing part 220 is in the free state, it provides room for welding the tab 301 and the pole post 4, which facilitates the welding of the tab 301 and the pole post 4. After the tab 301 and the pole post 4 are welded, the fixing part 220 switches to the fixed state, and the positioning post 221 passes through the first through hole 201 and is inserted into the positioning hole 101, so that the first plastic part 2 and the cover plate are connected. The plate body 1 is fixedly connected, and the fixing part 220 covers the tab 301. The fixing part 220 and the main body 210 clamp the tab 301. The fixing part 220 presses the tab 301 tightly onto the pole post 4. Relying on the compaction effect of the fixing part 220, the tab 301 is always fixed between the fixing part 220 and the main body 210 without deformation, which plays the role of fixing and shaping the tab, ensuring that the shape of the tab 301 remains unchanged. The fixing part 220 also separates the free end of the tab 301 from the pole group 3, preventing the tab 301 from being inserted backward into the pole group 3, reducing the probability of short circuit in the cell, and improving the safety performance of the cell.

[0072] It should be noted that the free end of the tab 301 refers to the end of the tab 301 that is away from the connection with the electrode group body. During the cell assembly process, the tab 301 is first welded to the electrode post 4, and then needs to be bent as the cover plate assembly is flipped. The several layers of metal foil on the tab 301 have different shapes and are prone to deformation before and after bending, and may be inserted into the electrode group 3 upside down. In this embodiment, the cover plate assembly relies on the pressing action of the fixing part 220 to keep the tab 301 fixed between the main body part 210 and the fixing part 220 without deformation, which can avoid the problem of the free end of the tab 301 being inserted into the electrode group 3 upside down.

[0073] In one embodiment, further combination Figure 12 As shown, the positioning hole 101 is a blind hole, and the area of ​​the bottom surface 1011 of the positioning hole 101 is larger than the opening area of ​​the positioning hole 101; further combined with Figure 27As shown, the positioning post 221 includes a post portion 2211 and a head 2212. At least a portion of the post portion 2211 passes through the first through hole 201, and the head 2212 is located in the positioning hole 101 and engages with the positioning hole 101. It should be noted that the opening of the positioning hole 101 faces the direction of the first plastic part 2, and the bottom surface 1011 refers to the surface of the positioning hole 101 opposite to its opening end. After engaging with the positioning hole 101, the positioning post 221 has a post portion 2211 and a head 2212. The cross-sectional area of ​​the head 2212 is larger than the cross-sectional area of ​​the post portion 2211, and the head 2212 is engaged in the positioning hole 101. By setting the positioning hole 101 as a blind hole, and ensuring that the area of ​​the bottom surface 1011 of the positioning hole 101 is larger than its opening area, the head 2212 of the positioning post 221 can be engaged in the positioning hole 101, achieving a snap-fit ​​between the positioning post 221 and the positioning hole 101. This securely connects the fixing part 220 to the cover plate body 1. The snap-fit ​​design makes it difficult for the positioning post 221 to come out of the positioning hole 101. Furthermore, after the positioning post 221 is engaged with the positioning hole 101, the fixing part 220 presses the main body 210 against the cover plate body 1, further ensuring the relative stability of the first plastic part 2 and the cover plate body 1. Moreover, by setting the positioning hole 101 as a blind hole, compared with a through hole, not only can the damage to the structural strength of the cover plate body 1 be reduced, but the sealing performance of the cover plate body 1 can also be avoided, thereby ensuring the reliability of the cover plate body 1.

[0074] Preferably, in the thickness direction of the cover plate body 1, i.e. Figure 27 The Z direction indicated by the middle arrow, along the direction from the opening end of the positioning hole 101 to the bottom surface 1011, the outline of the positioning hole 101 on the cross section perpendicular to the Z direction gradually increases; the cross section of the head 2212 of the positioning post 221 is larger than the cross section of the post 2211, thereby realizing the snap-fit ​​of the head 2212 in the positioning hole 101.

[0075] In one embodiment, the positioning post 221 is fitted into the positioning hole 101 via heat fusion. It should be noted that before heat fusion, the positioning post 221 is a common, uniform cross-section column. During heat fusion, the portion of the positioning post 221 extending into the positioning hole 101 melts and deforms to fill the positioning hole 101, and after cooling and solidification, forms a head 2212 that matches the shape of the positioning hole 101. The heat fusion method eliminates the need for additional connectors, resulting in a simple structure, convenient operation, reduced costs, high connection strength, structural stability, and long-term reliability.

[0076] In other embodiments, the positioning post 221 may also include a post portion 2211 and a head 2212 during the processing and molding process. In the cross-section perpendicular to the axis of the post portion 2211, the cross-sectional area of ​​the head 2212 is larger than that of the post portion 2211. Since the first plastic part 2 is a plastic part, it has a certain elasticity, that is, the positioning post 221 has a certain elastic deformation. When assembling the positioning post 221 with the positioning hole 101, the head 2212 can be inserted into the positioning hole 101 by squeezing the head 2212. After the head 2212 enters the positioning hole 101, it rebounds, which can also achieve a tight fit with the positioning hole 101. That is, the positioning post 221 is engaged with the positioning hole 101 through the head 2212, which is reliable and has high stability.

[0077] It should be noted that further integration Figure 23 As shown, the battery cell has X, Y, and Z directions that intersect each other, preferably with the X, Y, and Z directions being perpendicular to each other.

[0078] In one embodiment, further combination Figure 27 As shown, the dimension of the column portion 2211 along the X and / or Y directions is d, and the dimension of the first through hole 201 along the X and / or Y directions is D, where D is greater than d. Here, the X direction refers to... Figure 2 , Figures 23 to 28 The direction indicated by the middle arrow ("X") is the direction of the Y direction. Figure 2 , Figure 23 The direction indicated by the middle arrow is "Y". By setting the size of the first through hole 201 in the X and / or Y directions to be larger than the size of the post 2211 in the X and / or Y directions, it is ensured that the positioning post 221 can pass smoothly through the first through hole 201, thereby ensuring that the positioning post 221 can be easily inserted into the positioning hole 101, and ensuring process yield.

[0079] In one embodiment, the positioning post 221 is cylindrical before hot melting, the post portion 2211 is cylindrical, and the first through hole 201 is a circular hole. Then d is the diameter of the post portion 2211 and D is the hole diameter of the first through hole 201. The cylindrical and circular hole structure is easy to process and form, and convenient to assemble.

[0080] In other embodiments, the column portion 2211 can also be a polygonal column such as a triangular column or a square column, and the first through hole 201 is a polygonal hole corresponding to the column portion 2211, which can also achieve assembly.

[0081] In one embodiment, the dimension d of the post 2211 along the X and / or Y directions ranges from 1.5mm to 3.5mm. The post 2211 connects the body portion of the fixing portion 220 to the head 2212. If d is less than 1.5mm, the post 2211 is too thin, resulting in insufficient structural strength and poor connection reliability; if d is greater than 3.5mm, the post 2211 is too thick, wasting material, increasing weight, and increasing cost. Therefore, by limiting d to the range of 1.5mm to 3.5mm, the structural strength of the positioning post 221 and the reliability of the connection between the fixing portion 220 and the cover plate body 1 can be guaranteed, thereby improving the safety of the battery cell, while also avoiding material waste and saving costs.

[0082] Optionally, the value of d is any one of 1.5mm, 1.7mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.5mm or a value between any two of these values.

[0083] In one embodiment, the dimension D of the first through hole 201 along the X and / or Y directions ranges from 1.8mm to 3.8mm. If D is less than 1.8mm, the opening size of the first through hole 201 is too small, making processing difficult and hindering the smooth passage of the positioning post 221. If D is greater than 3.8mm, the opening size of the first through hole 201 is too large, resulting in an excessively large gap between the hole wall of the first through hole 201 and the post portion 2211 of the positioning post 221, leading to a loose fit and poor stability. Therefore, by limiting D to a value between 1.8mm and 3.8mm, it is possible to ensure the smooth processing and forming of the first through hole 201, and the smooth passage of the positioning post 221, thus guaranteeing process yield. It also ensures the tight fit between the positioning post 221 and the first through hole 201, thereby ensuring the relative stability between the fixing part 220 and the main body part 210 and improving the reliability of the cover plate assembly.

[0084] Optionally, the value of D is any one of 1.8mm, 2mm, 2.2mm, 2.5mm, 2.8mm, 3mm, 3.3mm, 3.5mm, 3.8mm or a value between any two of these values.

[0085] It should be noted that the pole post 4 includes a plate, a column segment, and a riveting part. The column segment is connected between the plate and the riveting part. The plate is located on the side of the cover plate body 1 near the first plastic part 2. A portion of the main body 210 of the first plastic part 2 extends into the space between the plate and the cover plate body 1 around the second through hole 202. The riveting part is located on the side of the cover plate body 1 away from the first plastic part 2. A second plastic part is provided between the riveting part and the cover plate body 1. A sealing ring is provided between the column segment and the hole wall of the pole post through hole.

[0086] In one embodiment, further combination Figure 6 , Figures 26 to 28 As shown, the main body 210 includes a plastic body 211 and a protruding structure 212. The protruding structure 212 is connected to the side of the plastic body 211 facing away from the cover plate body 1. When the fixing part 220 is in a fixed state, the side of the protruding structure 212 facing away from the plastic body 211 abuts against the side of the fixing part 220 facing the main body 210. It should be noted that after the pole post 4 is assembled with the cover plate body 1 and the main body 210, the plate of the pole post 4 protrudes from the surface of the plastic body 211 facing away from the cover plate body 1 along the Z direction, and the electrode ear 301 is welded to the plate. Along the Z direction, there is a certain gap between the plastic body 211 and the fixing part 220 to accommodate the part of the plate protruding from the plastic body 211 and the electrode ear 301. By constructing a protruding structure 212 on the main body 210, when the fixing part 220 is in a fixed state, the protruding structure 212 is supported between the plastic body 211 and the fixing part 220, so that there is a stable gap space between the plastic body 211 and the fixing part 220, thereby providing a space for the tab 301 to be accommodated, avoiding excessive pressure damage to the tab 301, and thus ensuring the reliability of the battery cell.

[0087] In one embodiment, the first through hole 201 penetrates the protrusion structure 212 and the plastic body 211 along the Z direction. It should be noted that after the first through hole 201 is constructed, the remaining solid portion of the protrusion structure 212 surrounds the circumference of the first through hole 201 in a ring shape. By setting the first through hole 201 to penetrate the protrusion structure 212 and the plastic body 211 along the Z direction, not only is the dimension of the first through hole 201 along the Z direction increased, improving the stability of the structure after the first through hole 201 is opened in the main body 210, but the protrusion structure 212 also surrounds the outer periphery of the column portion 2211 of the positioning post 221, further improving the stability of the positioning post 221, thereby improving the reliability of the cover plate assembly.

[0088] In one embodiment, further combination Figure 28As shown, the dimension of the first through hole 201 along the Z direction is H1, where the value of H1 ranges from 0.8mm to 3.2mm. It should be noted that the dimension of the first through hole 201 along the Z direction is equal to the vertical distance between the surface of the plastic body 211 facing the cover plate body 1 and the surface of the fixing part 220 facing the cover plate body 1. This directly affects the distance between the plastic body 211 and the fixing part 220. If H1 is less than 0.8mm, the distance between the plastic body 211 and the fixing part 220 is too small, which may damage the tab 301 and affect the current carrying capacity of the battery cell. If H1 is greater than 3.2mm, the distance between the plastic body 211 and the fixing part 220 is too large, and the tab 301 cannot be effectively pressed, which may cause the tab to loosen or move and damage the tab 301. Therefore, by limiting H1 to a value within the range of 0.8mm to 3.2mm, it is possible to ensure that there is sufficient space between the fixing part 220 and the main body part 210 for the tab 301 to avoid damaging the tab 301, and also to ensure the compaction of the fixing part 220 on the tab 301 to prevent the tab 301 from loosening or moving and to avoid damaging the tab 301, thereby ensuring the overcurrent capacity of the battery cell.

[0089] Optionally, the value of H1 is any one of 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.2mm or a value between any two of these values.

[0090] In one embodiment, further combination Figure 27 As shown, the dimension of the plastic body 211 along the Z direction is h, where the value of h ranges from 0.45mm ≤ h ≤ 1.2mm. h represents the thickness of the plastic body 211. If h is less than 0.45mm, the thickness of the plastic body 211 is too small, resulting in insufficient structural strength and poor structural stability. If h is greater than 1.2mm, the thickness of the plastic body 211 is too large, leading to excessive weight, wasted materials, increased costs, and excessive space occupied within the battery cell, which is detrimental to improving the energy density of the battery cell. Therefore, by limiting h to a value between 0.45mm and 1.2mm, it is possible to ensure that the plastic body 211 has sufficient structural strength and stability, thereby improving the reliability of the cover assembly. This also avoids material waste, saves costs, and prevents excessive weight of the plastic body 211, reducing the space occupied by the plastic body 211 within the battery cell, which is beneficial for improving the energy density of the battery cell.

[0091] Optionally, the value of h is any one of 0.45mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 0.1mm, 1.2mm or a value between any two of these values.

[0092] In one embodiment, when the fixing part 220 is in a fixed state, the plastic body 211 and the fixing part 220 are parallel to each other. It should be noted that the tab 301 includes a positive tab and a negative tab, which are spaced apart. By setting the fixing part 220 to be parallel to the plastic body 211 when in a fixed state, the plastic body 211 and the fixing part 220 are evenly spaced, thereby ensuring that the fixing part 220 has the same compaction effect on the tabs 301 at different positions. This avoids local damage or loosening of the tabs 301, thereby improving the stability of the tabs 301 and ensuring flow capacity. Here, "tabs 301 at different positions" refers to different tabs (i.e., positive and negative tabs), or different positions along the X direction on the same tab 301.

[0093] In one embodiment, further combination Figure 7 and Figure 28 As shown, the dimension of the bent portion 230 along the Z direction is H2. The side of the bent portion 230 facing the cover plate body 1 is flush with the side of the plastic part body 211 facing the cover plate body 1. The side of the bent portion 230 away from the cover plate body 1 along the Z direction abuts against the surface of the fixed portion 220 which is in a fixed state. H2 and H1 satisfy: H2 = H1, thereby ensuring that the plastic part body 211 and the fixed portion 220 remain parallel.

[0094] In one embodiment, further combination Figures 2 to 4 As shown, the dimension of the bending portion 230 along the Y direction is smaller than the dimension of the main body portion 210 along the Y direction. By setting the dimension of the bending portion 230 along the Y direction to be smaller than the dimension of the main body portion 210 along the Y direction, the structural strength of the bending portion 230 is less than the structural strength of the main body portion 210 and the fixing portion 220, thereby facilitating the bending of the first plastic part 2 from the bending portion 230, reducing the difficulty of operation, and improving work efficiency.

[0095] Preferably, the dimension of the fixing part 220 along the Y direction is equal to the dimension of the main body part 210 along the Y direction.

[0096] In one embodiment, the cover plate body 1 has an explosion-proof valve hole, the main body 210 has a third through hole 203 corresponding to the explosion-proof valve hole, and the fixing part 220 has a venting area 222 corresponding to the third through hole 203, with a venting hole 223 in the venting area 222. By opening an explosion-proof valve hole on the cover plate body 1 and providing the third through hole 203 and venting hole 223 corresponding to the explosion-proof valve hole on the main body 210 and fixing part 220 of the first plastic part 2 respectively, the first plastic part 2 is prevented from blocking the explosion-proof valve hole. This allows the gas inside the battery cell to be discharged to the outside of the battery cell in sequence through the venting hole 223, the third through hole 203, and the explosion-proof valve hole when thermal runaway occurs, ensuring smooth exhaust and improving the safety performance of the battery cell.

[0097] In one embodiment, the cover plate assembly further includes an explosion-proof valve 5, which is installed in an explosion-proof valve hole. The explosion-proof valve 5 is adapted to open when the gas pressure inside the battery cell increases to a certain value, thereby venting the high-temperature and high-pressure flue gas inside the battery cell to the outside of the battery cell, preventing the battery cell from exploding due to excessive internal gas pressure, and thus ensuring the safety of the battery cell.

[0098] It should be noted that the battery cell assembly process is as follows: First, the terminal post 4 and explosion-proof valve 5, etc., are installed onto the cover plate body 1; then, the first plastic part 2 is placed in a free state (e.g., Figures 1 to 7 (As shown) is assembled with the cover plate body 1 to form a cover plate assembly, wherein the main body 210 of the first plastic part 2 is fitted to the cover plate body 1, and the pole post 4 passes through the second through hole 202 on the main body 210. The assembled structure is as follows. Figures 8 to 13 As shown; then, the electrode assembly 3 is assembled with the cover plate assembly described above. At this time, the electrode tabs 301 on the electrode assembly 3 are not bent, and the cover plate body 1 and the end face on the electrode post 4 where the electrode tabs 301 are provided are perpendicular. The electrode tabs 301 are directly attached to the electrode post 4 exposed through the second through hole 202, and then the electrode tabs 301 and the electrode post 4 are welded to form as shown. Figures 14 to 17 The form shown is as follows; subsequently, the fixing part 220 is folded around the bending part 230 to switch the fixing part 220 to a fixed state, so that the fixing part 220 is fastened to the main body part 210, and the positioning post 221 passes through the first through hole 201 on the main body part 210 and is inserted into the positioning hole 101 on the cover plate body 1, and the positioning post 221 is heat-melted, so that the positioning post 221 melts and fills the positioning hole 101, and after cooling and solidification, it forms an undercut fit with the positioning hole 101, realizing the fixed connection between the first plastic part 2 and the cover plate body 1 (e.g. Figures 18 to 22 As shown), the fixing part 220 presses down on the electrode tab 301, thereby fixing and shaping the electrode tab 301; then, the cover plate assembly is folded up until the end face of the cover plate body 1 and the electrode group 3 on which the electrode tab 301 is provided is parallel (core fitting), and the electrode tab 301 is bent accordingly to form an insert structure (as shown). Figures 23 to 30 (as shown); Finally, the above-obtained housing structure is installed into the housing, the cover plate assembly is located at the open end of the housing, and the cover plate body 1 is welded to the housing to obtain the battery cell.

[0099] According to an embodiment of the present invention, another aspect provides a battery cell, comprising: a housing, an electrode assembly 3, and the aforementioned cover plate assembly. The housing has an open end; the electrode assembly 3 is located in the inner cavity of the housing, and the electrode assembly 3 has an electrode tab 301; the cover plate assembly covers the open end of the housing, and the electrode post 4 in the cover plate assembly is welded to the electrode tab 301, the electrode tab 301 being located between the main body portion 210 and the fixing portion 220 of the first plastic part 2.

[0100] In this embodiment, the battery cell includes a first plastic part 2 comprising a main body 210, a bending part 230, and a fixing part 220 connected in sequence. After the tab 301 is welded to the electrode post 4 integrated on the cover plate body 1, the fixing part 220 is folded over the main body 210 to cover the tab area by the bending property of the bending part 230. The positioning post 221 on the fixing part 220 is melted into the positioning hole 101 on the cover plate body 1. The positioning post 221 and the positioning hole 101 are interlocked to form a fixed connection, ensuring the connection strength between the fixing part 220 and the cover plate body 1. After the electrode assembly is completed, the tab 301 is always fixed between the main body 210 and the fixing part 220 without deformation due to the compaction effect of the fixing part 220. This ensures that the shape of the tab 301 remains unchanged before and after the electrode assembly, thus fixing and shaping the tab, reducing the probability of short circuit in the battery cell, and improving the safety performance of the battery cell.

[0101] Optionally, the battery cell is a lithium-ion battery cell.

[0102] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A cover plate assembly, characterized in that, include: The cover plate body has a first surface formed on the first side along the Z direction. The cover plate body is provided with a pole through hole and a positioning hole. The positioning hole is constructed on the first surface. The electrode post is inserted into the through hole of the electrode post and is suitable for welding to the electrode lug; The first plastic part includes a main body, a fixing part, and a bending part. The main body is disposed on the first side of the cover plate body. The main body has a first through hole corresponding to the positioning hole and a second through hole corresponding to the pole through hole. The bending part is connected between the main body and the fixing part. The fixing part can be folded relative to the main body around the bending part. The fixing part has a free state of folding relative to the main body and a fixed state of being fastened to the main body. The fixing part is provided with a positioning post. When the fixing part is in the fixed state, the positioning post passes through the first through hole and cooperates with the positioning hole. The fixing part and the main body part are adapted to clamp the electrode tab.

2. The cover plate assembly according to claim 1, characterized in that, The positioning hole is a blind hole, and the area of ​​the bottom surface of the positioning hole is larger than the area of ​​the opening of the positioning hole; the positioning post includes a post part and a head, at least a portion of the post part is inserted into the first through hole, and the head is located in the positioning hole and cooperates with the positioning hole.

3. The cover plate assembly according to claim 2, characterized in that, The positioning post is fitted into the positioning hole by heat fusion.

4. The cover plate assembly according to claim 2, characterized in that, The dimension of the column portion along the X and / or Y directions is d, and the dimension of the first through hole along the X and / or Y directions is D, wherein D is greater than d.

5. The cover plate assembly according to claim 4, characterized in that, The dimension d of the column along the X and / or Y directions ranges from 1.5mm to 3.5mm. And / or, the dimension D of the first through hole along the X direction and / or Y direction is in the range of 1.8mm≤D≤3.8mm.

6. The cover plate assembly according to claim 1, characterized in that, The main body includes a plastic body and a protruding structure. The protruding structure is connected to the side of the plastic body away from the cover plate body. When the fixing part is in the fixed state, the side of the protruding structure away from the plastic body abuts against the side of the fixing part facing the main body.

7. The cover plate assembly according to claim 6, characterized in that, The first through hole penetrates the protruding structure and the plastic body along the Z direction.

8. The cover plate assembly according to claim 7, characterized in that, The dimension of the first through hole along the Z direction is H1, wherein the value of H1 is in the range of 0.8mm≤H1≤3.2mm; And / or, the dimension of the plastic part body along the Z direction is h, wherein the value of h is in the range of: 0.45mm≤h≤1.2mm; And / or, when the fixing part is in the fixed state, the plastic body and the fixing part are parallel to each other.

9. The cover plate assembly according to any one of claims 1 to 8, characterized in that, The dimension of the bent portion along the Y direction is smaller than the dimension of the main body portion along the Y direction; And / or, the cover plate body is provided with an explosion-proof valve hole, the main body is provided with a third through hole corresponding to the explosion-proof valve hole, the fixing part is provided with a venting area corresponding to the third through hole, and the venting area is provided with a venting hole.

10. A battery cell, characterized in that, include: The shell has an open end; An electrode assembly, located within the inner cavity of the housing, has electrode tabs; The cover plate assembly according to any one of claims 1 to 9 is provided covering the opening end of the housing, wherein the pole post in the cover plate assembly is welded to the pole lug, and the pole lug is located between the main body portion and the fixing portion of the first plastic part.

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