Battery cell and battery pack

Abstract

The utility model relates to battery technology field discloses electric core and battery package. Electric core includes: casing, has open end, cover plate subassembly, sets up in the open end of casing, cover plate subassembly includes cover plate body, first plastic piece, first plastic piece sets up in the one side of the inner chamber of cover plate body to casing, and first plastic piece includes plastic piece body and buckle, and the buckle fixed connection is established in the one side of first plastic piece away from cover plate body, pole group includes pole group body and pole lug, and the one end of pole group body to cover plate subassembly is first end surface, and the pole lug is bent and is directed to first end surface by the pole group body and is stretched out, support piece, at least partial setting between pole lug and first end surface, and the clamping hole is seted up on support piece, and the clamping hole is arranged with the interval to pole lug, and the clamping hole is clamped with buckle. The problem that pole lug is easy to tear and is easy to insert into pole group body is solved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to battery cells and battery packs. Background Technology

[0002] A battery cell consists of a housing, electrode assembly, and cover plate assembly. The electrode assembly is located within the inner cavity of the housing, and the cover plate assembly covers the open end of the housing. The tabs on the electrode assembly are electrically connected to the terminals in the cover plate assembly. In existing technology, a connecting piece is provided between the electrode assembly and the terminal, with one side of the connecting piece welded to the terminal and the other side welded to the tab. However, since the tab usually needs to be bent before welding to the connecting piece, and the tab is composed of several layers of metal foil, the structural strength of the tab is relatively weak, making it prone to tearing. This leads to a decrease in the current carrying capacity of the battery cell tab, or the tab may be inserted backwards into the electrode assembly body after bending, causing a short circuit inside the battery cell and affecting the safety and stability of the battery cell. Utility Model Content

[0003] In view of this, the present invention provides a battery cell and battery pack to solve the problems of the tabs being easily torn and easily inserted backwards into the electrode assembly body.

[0004] In a first aspect, this utility model provides a battery cell, comprising: a housing having an open end; a cover plate assembly disposed at the open end of the housing, the cover plate assembly including a cover plate body and a first plastic part, the first plastic part being disposed on the side of the cover plate body facing the inner cavity of the housing, the first plastic part including a plastic part body and a buckle, the buckle being fixedly connected to the side of the first plastic part away from the cover plate body; an electrode assembly including an electrode assembly body and an electrode tab, the end of the electrode assembly body facing the cover plate assembly being a first end face, the electrode tab extending from the electrode assembly body and bent toward the first end face; and a support member at least partially disposed between the electrode tab and the first end face, the support member having a locking hole, the locking hole being spaced apart from the electrode tab, the locking hole engaging with the buckle.

[0005] Beneficial effects: By setting a support member between the tab and the first end face of the electrode assembly, and by having the support member engage with the snap-fit ​​on the first plastic part in the cover plate assembly through its snap-fit ​​hole, the support member and the first plastic part are fixedly connected, ensuring the stability of the support member's position in the cell. This, in turn, supports and fixes the tab, improving the stability of the tab in the cell and preventing the tab from tearing. This avoids the problem of reduced current carrying capacity of the cell caused by tab tearing. Furthermore, the tab is fixed between the support member and the cover plate assembly, which has a shaping effect on the tab, making the tab shape more neat. The support member also separates the bent part of the tab from the electrode assembly body, which can prevent the tab from being too scattered or too long and inserted upside down into the electrode assembly body, thus avoiding short circuits inside the cell and further improving the safety and stability of the cell.

[0006] In one optional embodiment, the buckle includes a rod and a head, the rod connecting the plastic body and the head, the axis of the rod extending along the Z direction, and the cross-sectional area of ​​the head in the XY plane being larger than the cross-sectional area of ​​the rod in the XY plane; the locking hole includes a first hole segment and a second hole segment, the second hole segment being connected to the end of the first hole segment away from the cover plate body, the diameter of the second hole segment being larger than the diameter of the first hole segment, and the head being engaged in the second hole segment.

[0007] Beneficial effects: By setting the cross-sectional area of ​​the head of the buckle to be larger than that of the rod, and the buckling hole consisting of a first hole segment close to the plastic part body and a second hole segment away from the plastic part body, and the diameter of the second hole segment being larger than that of the first hole segment, when the head passes through the first hole segment and enters the second hole segment, the head is engaged in the second hole segment. Thus, the engagement between the support and the first plastic part can be achieved through the engagement of the buckle and the buckling hole, resulting in high connection stability, preventing the support from detaching from the cover plate assembly, and improving the overall assembly stability and reliability.

[0008] In one optional embodiment, the dimension of the support member along the Z direction is h, and the dimension of the first hole segment along the Z direction is h1, wherein h1 and h satisfy the relationship: 1 / 3≤h1 / h≤2 / 3.

[0009] Beneficial effects: It can ensure the snap-fit ​​effect and snap-fit ​​strength between the support and the first plastic part, improve the stability of the support, and avoid the buckle from damaging the electrode group, thus improving the safety of the battery cell.

[0010] In one optional embodiment, the dimension h of the support member along the Z direction is in the range of 0.5 mm ≤ h ≤ 5 mm.

[0011] Beneficial effects: It can ensure that the support has sufficient structural strength to provide effective support for the tabs, and avoid occupying too much space inside the cell along the Z direction, which is conducive to improving the energy density of the cell, reducing costs, and achieving lightweighting.

[0012] In one optional embodiment, the support member has a through portion, which is spaced apart from the card hole.

[0013] Beneficial effects: The through-hole and the snap hole are spaced apart, so the through-hole will not affect the snap-fit ​​between the support and the first plastic part. The through-hole can reduce the material of the support and reduce its weight. It can also ensure that the electrolyte can flow through the through-hole to the electrode group during the liquid injection process, avoiding the electrolyte from being stored on the support and avoiding the waste of electrolyte.

[0014] In one alternative embodiment, the cover plate assembly further includes a terminal post, and the battery cell further includes a connecting piece. The connecting piece includes a terminal post connecting portion and a tab connecting portion. The terminal post connecting portion is electrically connected to the terminal post, and the tab connecting portion is located between the first plastic part and the tab, and the tab connecting portion is electrically connected to the tab.

[0015] Beneficial effects: By setting connecting pieces in the electrode assembly and cover plate assembly, and the connecting pieces include electrode post connecting parts connected to the electrode post and electrode tab connecting parts connected to the electrode tab, the electrical connection between the electrode tab and the electrode post is realized through the connecting pieces, which has good stability and facilitates the assembly of the battery cell.

[0016] In one optional embodiment, along the Z direction, the distance between the plastic body and the support is h2, the thickness of the tab is h3, and the thickness of the tab connection is h4, wherein h2, h3 and h4 satisfy the relationship: 0 < h2 - h3 - h4 ≤ 2 mm.

[0017] Beneficial effects: It can prevent the connecting piece from directly contacting the first plastic part, thereby preventing the heat generated when the connecting piece is welded to the electrode tab from being transferred to the first plastic part and causing the first plastic part to melt. It can also prevent the connecting piece from damaging the first plastic part, thereby ensuring the stability and reliability of the first plastic part, ensuring that it has good insulation performance, improving the safety of the battery cell, and making full use of the internal space of the battery cell to increase the volumetric energy density of the battery cell.

[0018] In one optional embodiment, the thickness h4 of the electrode connection portion is in the range of 0.4 mm ≤ h4 ≤ 1 mm; And / or, the thickness h3 of the electrode tab is in the range of 0.1 mm ≤ h3 ≤ 1 mm.

[0019] Beneficial effects: By limiting h4 to a value within the range of 0.4 mm to 1 mm, the tab connection part has a reasonable thickness, which can ensure that the tab connection part has sufficient structural strength and avoid the tab connection part being welded through during the welding process with the tab, thereby improving the reliability of the tab connection part and ensuring the stability of the connection between the tab connection part and the tab. It can also control the weight of the connecting piece, reduce costs, and improve the internal space utilization of the cell, which is conducive to improving the energy density of the cell. And / or, by limiting h3 to a value within the range of 0.1 mm to 1 mm, it is possible to avoid tearing of the tabs, ensure the reliability of the tabs, and reduce weight, thereby achieving lightweighting of the battery cell.

[0020] In one optional embodiment, the distance between the support member and the pole group body along the Z direction is h5, wherein the value of h5 is in the range of 0≤h5≤5 mm. And / or, the number of the pole groups is two, the two pole groups are arranged side by side along the Y direction, each pole group includes a first pole and a second pole, the number of the support members is two, one support member is arranged corresponding to the two first poles, and the other support member is arranged corresponding to the two second poles.

[0021] Beneficial effects: By limiting h5 to a value between 0 and 5 mm, it is possible to avoid the support component damaging the electrode assembly body, thereby improving the safety of the battery cell. It is also possible to ensure the relative stability between the support component and the electrode assembly body, thereby improving the internal space utilization of the battery cell and thus improving the energy density of the battery cell. And / or, by setting the number of pole groups to two, and having the same polarity poles in the two pole groups share a support, the number of support components can be reduced, the internal space utilization of the cell can be improved, and the cell assembly can be facilitated.

[0022] Secondly, this utility model also provides a battery pack, including the aforementioned battery cell. Since the battery pack includes the battery cell and has the same effects as the battery cell, it will not be described in detail here. Attached Figure Description

[0023] 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.

[0024] Figure 1 This is a schematic diagram of an electrical structure according to an embodiment of the present utility model; Figure 2 for Figure 1 The diagram shows the structure of the battery cell from the bottom view. Figure 3 for Figure 1 The diagram shows the electrical properties in an exploded view. Figure 4 for Figure 1 A top view of the battery cell shown; Figure 5 for Figure 4 A cross-sectional view along the AA direction; Figure 6 for Figure 5 A magnified view of part of C; Figure 7 for Figure 6 A magnified view of part of D; Figure 8 for Figure 4 Cross-sectional view along the BB direction; Figure 9 for Figure 8 A magnified view of a portion of the component near the cover plate; Figure 10 This is a bottom view structural diagram of the cover plate assembly and pole assembly structure according to an embodiment of the present utility model; Figure 11 for Figure 10 A schematic diagram of the assembly structure after removing one pole group; Figure 12 for Figure 11 A magnified view of part of E in the diagram; Figure 13 This is a structural schematic diagram of a support member from the bottom view according to an embodiment of the present utility model; Figure 14 for Figure 13 Top view of the support member shown; Figure 15 for Figure 14 A cross-sectional view along the FF direction; Figure 16 This is a schematic diagram of the structure of a cover plate assembly according to an embodiment of the present utility model; Figure 17 for Figure 16 A structural schematic diagram of the cover plate assembly from the bottom view; Figure 18 for Figure 17 A magnified view of a portion of G; Figure 19 This is a schematic diagram of the structure of a cover plate assembly and connecting piece after assembly according to an embodiment of the present utility model; Figure 20 This is a schematic diagram of the structure of a connecting piece according to an embodiment of the present utility model.

[0025] Explanation of reference numerals in the attached figures: 10. Shell; 20. Cover plate body; 201. Injection hole; 202. Hole plug; 203. Hole cover; 30. First plastic part; 301. Plastic part body; 302. Buckle; 3021. Rod; 3022. Head; 40. Electrode assembly; 401. Electrode assembly body; 4011. First end face; 402. Electrode tab; 4021. Extension; 4022. Bending part; 50. Support member; 501. Locking hole; 502. Through part; 5011. First hole section; 5012. Second hole section; 60. Electrode post; 61. Riveting block; 62. Second plastic part; 70. Connecting piece; 701. Electrode post connecting part; 702. Electrode tab connecting part; 7021. First connecting section; 7022. Second connecting section; 80. Explosion-proof valve; 90. Insulating film. Detailed Implementation

[0026] 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.

[0027] A connecting piece 70 is provided between the electrode assembly 40 and the cover plate assembly of the battery cell. The connecting piece 70 connects the tab 402 and the terminal post 60. The tab 402 extends from one end of the electrode assembly body 401. In order to facilitate the connection between the tab 402 and the connecting piece 70, the tab 402 usually needs to be bent. However, the bent tab 402 may be inserted backward into the electrode assembly body 401, causing a short circuit inside the battery cell and affecting the safety performance of the battery cell. In addition, the electrode assembly is composed of a positive electrode plate, a negative electrode plate and a separator. The tab extends from the metal foil layer in the electrode plate. The structural strength of the tab is relatively weak. During the assembly or use of the battery cell, when subjected to external force, the tab is prone to tearing, which leads to a decrease in the current carrying capacity of the battery cell tab and affects the stability of the battery cell performance.

[0028] The following is combined Figures 1 to 20 The following describes embodiments of the present invention.

[0029] According to an embodiment of the present invention, a battery cell is provided, comprising: a housing 10, a cover plate assembly, an electrode group 40, and a support member 50. The housing 10 has an open end; a cover plate assembly is disposed at the open end of the housing, the cover plate assembly includes a cover plate body 20 and a first plastic part 30, the first plastic part 30 is disposed on the side of the cover plate body 20 facing the inner cavity of the housing, the first plastic part 30 includes a plastic part body 301 and a buckle 302, the buckle 302 is fixedly connected to the side of the first plastic part 30 away from the cover plate body 20; the electrode assembly 40 includes an electrode assembly body 401 and an electrode tab 402, the end of the electrode assembly body 401 facing the cover plate assembly is a first end face 4011, the electrode tab 402 extends from the electrode assembly body 401 and bends toward the first end face 4011; a support member 50 is at least partially disposed between the electrode tab 402 and the first end face 4011, the support member 50 has a locking hole 501, the locking hole 501 is spaced apart from the electrode tab 402, and the locking hole 501 is engaged with the buckle 302.

[0030] It should be noted that the battery cell has X, Y, and Z directions that intersect each other, and preferably, the X, Y, and Z directions are perpendicular to each other (e.g., ...). Figures 1 to 15(As shown). At least one end of the housing 10 along the Z direction is an open end; the end of the pole assembly body 401 along the Z direction facing the cover plate assembly is a first end face 4011; the pole tab 402 extends from the pole assembly body 401 and bends toward a plane parallel to the first end face 4011, that is, the pole tab 402 extends from the pole assembly body 401 along the Z direction and then bends toward the XY plane.

[0031] In the battery cell of this embodiment, a support member 50 is provided between the tab 402 and the first end face 4011 of the electrode assembly body 401. The support member 50 is engaged with the first plastic part 30 in the cover plate assembly through the snap-fit ​​hole 501 on it, thereby achieving a fixed connection between the support member 50 and the first plastic part 30. This ensures the stability of the position of the support member 50 in the battery cell, and further supports and fixes the tab 402, improving the stability of the tab 402 in the battery cell and preventing the tab 402 from tearing. This avoids the problem of reduced current carrying capacity of the battery cell due to tearing of the tab 402. Furthermore, the tab 402 is fixed between the support member 50 and the cover plate assembly by the support member 50, which has a shaping effect on the tab 402, making the tab 402 more neat. In addition, the support member 50 separates the bent part of the tab 402 from the electrode assembly body 401, which can avoid the problem of the tab 402 being too scattered or the tab being too long and inserted into the electrode assembly body 401 backwards, thus avoiding short circuits inside the battery cell and further improving the safety and stability of the battery cell.

[0032] Specifically, further integration Figures 8 to 9 As shown, the electrode tab 402 includes an extension 4021 and a bend 4022. The extension 4021 is connected to the electrode assembly body 401 and extends along the Z direction. The bend 4022 is connected to the end of the extension 4021 away from the electrode assembly body 401, and the bend 4022 is parallel to the XY plane. Here, the Z direction refers to... Figures 8 to 9 The direction indicated by the middle arrow, "Z", refers to the XY plane. Figures 1 to 3 The plane formed by the "X" and "Y" directions indicated by the middle arrow.

[0033] In one embodiment, further combination Figures 5 to 7As shown, the buckle 302 includes a rod 3021 and a head 3022. The rod 3021 is connected between the plastic body 301 and the head 3022. The axis of the rod 3021 extends along the Z direction. The cross-sectional area of ​​the head 3022 in the XY plane is greater than the cross-sectional area of ​​the rod 3021 in the XY plane. The locking hole 501 includes a first hole segment 5011 and a second hole segment 5012. The second hole segment 5012 is connected to the end of the first hole segment 5011 away from the cover plate body 20. The diameter of the second hole segment 5012 is greater than the diameter of the first hole segment 5011. The head 3022 is engaged in the second hole segment 5012. By setting the cross-sectional area of ​​the head 3022 of the buckle 302 to be larger than the cross-sectional area of ​​the rod 3021, the locking hole 501 is composed of a first hole segment 5011 close to the plastic body 301 and a second hole segment 5012 away from the plastic body 301, and the diameter of the second hole segment 5012 is larger than the diameter of the first hole segment 5011. When the head 3022 passes through the first hole segment 5011 and enters the second hole segment 5012, the head 3022 is locked in the second hole segment 5012. Thus, the locking of the support 50 and the first plastic part 30 can be achieved through the locking of the buckle 302 and the locking hole 501. The connection is highly stable, preventing the support 50 from detaching from the cover plate assembly, and improving the overall assembly stability and reliability.

[0034] Preferably, the rod portion 3021 is in the shape of a round rod, the locking hole 501 is a round hole, and the first hole segment 5011 and the second hole segment 5012 are concentrically arranged round holes; the cross-sectional area of ​​the rod portion 3021 along the XY plane is smaller than the diameter of the hole in the first hole segment 5011, and the cross-sectional area of ​​the head 3022 near the end of the rod portion 3021 is larger than the diameter of the hole in the first hole segment 5011.

[0035] Preferably, the plastic body 301 and the buckle 302 are integrally formed.

[0036] In one embodiment, the locking hole 501 is a through hole that passes through the support member 50 along the Z direction, which facilitates the processing of the locking hole 501 and the installation and engagement of the buckle 302 with the locking hole 501.

[0037] In one embodiment, the support member 50 is made of an insulating material to further ensure the insulation between the bent portion 4022 of the electrode tab 402 and the electrode assembly body 401. Optionally, the material of the support member 50 may be PP (Polypropylene), PE (Polyethylene), PC (Polycarbonate), etc.

[0038] In one embodiment, further combination Figure 7As shown, the dimension of the support member 50 along the Z direction is h, and the dimension of the first hole segment 5011 along the Z direction is h1. The relationship between h1 and h satisfies the formula: 1 / 3 ≤ h1 / h ≤ 2 / 3. Here, the units of h1 and h are both mm; the Z direction refers to... Figure 7 The direction indicated by the middle arrow is "Z". It should be noted that the sum of the dimensions h1 of the first hole segment 5011 along the Z direction and the second hole segment 5012 along the Z direction equals the dimension h of the support member 50 along the Z direction. A stepped structure is formed at the connection between the second hole segment 5012 and the first hole segment 5011. When the buckle 302 engages with the buckle hole 501, the step abuts against the head 3022. The hole depth of the first hole segment 5011 directly affects the supporting force of the support member 50 on the head 3022; if h1 / h is less than 1 / 3, then the hole depth of the first hole segment 5011 relative to the thickness of the support member 50... If the depth is too small, the snap-fit ​​effect is poor and the snap-fit ​​strength is weak, and the snap-fit ​​302 is prone to coming out of the snap-fit ​​hole 501. If h1 / h is greater than 2 / 3, the hole depth of the first hole section 5011 is too large relative to the thickness of the support member 50, resulting in the hole depth of the second hole section 5012 being too small. The head 3022 of the snap-fit ​​302 may protrude from the surface of the support member 50 along the Z direction away from the plastic body 301. As a result, the head 3022 may squeeze the electrode body 401, causing squeezing damage to the electrode body 401 and affecting the safety performance of the battery cell.

[0039] Therefore, by limiting h1 / h to a value between 1 / 3 and 2 / 3, the snap-fit ​​effect and snap-fit ​​strength between the support 50 and the first plastic part 30 can be guaranteed, improving the stability of the support 50, while also preventing the buckle 302 from damaging the electrode group and improving the safety of the battery cell.

[0040] Optionally, the value of h1 / h is any one of 1 / 3, 5 / 12, 1 / 2, 7 / 12, 2 / 3, or a value between any two of these values.

[0041] In one embodiment, the dimension h of the support member 50 along the Z direction ranges from 0.5 mm to 5 mm. If h is less than 0.5 mm, the support member 50 is too thin, resulting in poor structural strength, easy deformation, and poor engagement with the buckle 302, leading to engagement failure. The stability of the support member 50 is also poor, failing to provide effective support for the tab 402. If h is greater than 5 mm, the support member 50 is too thick, occupying excessive space within the cell along the Z direction, which is detrimental to space utilization, increases cost, and adds weight, hindering the improvement of the cell's energy density. Therefore, by limiting h to the range of 0.5 mm to 5 mm, it is possible to ensure that the support member 50 has sufficient structural strength to provide effective support for the tab 402, while avoiding excessive space occupation within the cell along the Z direction. This is beneficial for improving the cell's energy density, reducing costs, and achieving lightweight design.

[0042] Optionally, the value of h is any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, or a value between any two of these values.

[0043] In one embodiment, further combination Figures 13 to 14 As shown, the support member 50 has a through portion 502, which is spaced apart from the locking hole 501. It should be noted that the through portion 502 extends through the support member 50 along the Z-direction. The through portion 502 and the locking hole 501 are spaced apart, so the through portion 502 does not affect the locking between the support member 50 and the first plastic part 30. Furthermore, the through portion 502 can reduce the material of the support member 50, reducing its weight. It also ensures that the electrolyte can flow through the through portion 502 to the electrode assembly 40 during the injection process, preventing electrolyte from remaining on the support member 50 and avoiding electrolyte waste.

[0044] In one embodiment, the through portion 502 is a through groove. The through groove is easy to process, and can minimize the weight of the support member 50 while ensuring its structural strength and allowing the electrolyte to pass smoothly. Preferably, there are two through grooves, spaced apart along the Y direction, with a retaining hole 501 between them.

[0045] In other embodiments, the through portion 502 can also be configured as a round hole and / or a polygonal hole, and there can be multiple through portions 502, which can also reduce the weight of the support member 50 and ensure the smooth flow of electrolyte.

[0046] In one embodiment, further combination Figure 6 As shown, the cover plate assembly also includes a terminal post 60, and the battery cell also includes a connecting piece 70. The connecting piece 70 includes a terminal post connecting portion 701 and a tab connecting portion 702. The terminal post connecting portion 701 is electrically connected to the terminal post 60, and the tab connecting portion 702 is located between the first plastic part 30 and the tab 402, and is electrically connected to the tab 402. It should be noted that the tab connecting portion 702 is located between the first plastic part 30 and the bent portion 4022 of the tab 402, and is used for electrical connection with the bent portion 4022. Preferably, the tab connecting portion 702 is welded to the tab 402. By providing the connecting piece 70 between the electrode group 40 and the cover plate assembly, and the connecting piece 70 including a terminal post connecting portion 701 connected to the terminal post 60 and a tab connecting portion 702 connected to the tab 402, the electrical connection between the tab 402 and the terminal post 60 is achieved through the connecting piece 70, which has good stability and facilitates the assembly of the battery cell.

[0047] It should be noted that the pole post connection 701 and the tab connection 702 are arranged sequentially along the X direction. Optionally, the pole post connection 701 and the tab connection 702 are not on the same plane, and the connecting piece 70 is bent, which can adapt to the internal space of the battery cell and improve the utilization rate of the internal space of the battery cell.

[0048] In one embodiment, the cover plate body 20 is provided with a first through hole, the first plastic part 30 is provided with a second through hole corresponding to the first through hole, and the pole post 60 passes through the first through hole and the second through hole.

[0049] In one embodiment, the cover plate assembly further includes a riveting block 61, a second plastic part 62, and a sealing ring. The riveting block 61 is disposed on the side of the cover plate body away from the first plastic part 30 (i.e., the side facing the outside of the battery cell). The second plastic part 62 is disposed between the riveting block 61 and the cover plate body 20. The riveting block 61 has a third through hole corresponding to the first through hole. The pole post 60 includes a column and a plate. The column passes through the first through hole, the second through hole, and the third through hole and is riveted to the riveting block. The sealing ring is sleeved on the outer periphery of the column. The plate is located on the side of the first plastic part 30 away from the cover plate body 20. The plate is electrically connected to the connecting piece 70, preferably by welding.

[0050] It should be noted that the first plastic part 30 is the lower plastic part, and the second plastic part 62 is the upper plastic part.

[0051] In one embodiment, further combination Figure 7 As shown, along the Z-direction, the distance between the plastic body 301 and the support 50 is h2, the thickness of the tab 402 is h3, and the thickness of the tab connection 702 is h4. The relationships between h2, h3, and h4 are: 0 < h2 - h3 - h4 ≤ 2 mm. It should be noted that the Z-direction refers to... Figure 7 The direction indicated by the middle arrow "Z" is as follows: There is a certain gap (i.e., the first gap) between the plastic body 301 and the support member 50. The first gap is provided with the bent portion 4022 of the tab 402 and the tab connecting portion 702 of the connecting piece 70. h2-h3-h4 represents the difference between the first gap and the total thickness of the bent portion 4022 and the tab connecting portion 702. Since the bent portion 4022 is attached to the support member 50 and the tab connecting portion 702 is attached to the bent portion 4022, the difference is reflected as the gap between the plastic body 301 and the tab connecting portion 702. The dimension of the gap along the Z direction is h6=h2-h3-h4.

[0052] Since the tab 402 and the connecting piece 70 are connected by welding, welding heat will be generated during the welding process. If h2-h3-h4 equals 0, that is, the connecting piece 70 is in direct contact with the plastic body 301, a large amount of welding heat will be transferred to the first plastic part 30, which may cause the first plastic part 30 to melt, failing to provide good insulation and affecting the safety of the battery cell. If h2-h3-h4 is less than 0, not only will there be the problem of welding heat being transferred to the first plastic part 30, causing the first plastic part 30 to melt locally, but the plastic body 301 may also be easily damaged due to the connecting piece 70 pressing against it, which will also reduce the insulation of the first plastic part 30. If h2-h3-h4 is greater than 2 mm, the gap between the plastic body 301 and the tab connection part 702 will be too large, failing to fully utilize the space inside the battery cell along the Z direction, which is not conducive to improving the volumetric energy density of the battery cell.

[0053] Therefore, by limiting h2-h3-h4 to be greater than 0 and less than or equal to 2 mm, it is possible to avoid the connecting piece 70 directly contacting the first plastic part 30, thereby preventing the heat generated during the welding of the connecting piece 70 and the tab 402 from being transferred to the first plastic part 30 and causing the first plastic part 30 to melt. It is also possible to prevent the connecting piece 70 from damaging the first plastic part 30, thereby ensuring the stability and reliability of the first plastic part 30, ensuring its good insulation performance, improving the safety of the battery cell, and making full use of the internal space of the battery cell to increase the volumetric energy density of the battery cell.

[0054] Optionally, the values ​​of h2-h3-h4 are any one of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, or a value between any two of them.

[0055] In one embodiment, the thickness h4 of the tab connection 702 ranges from 0.4 mm to 1 mm. It should be noted that if h4 is less than 0.4 mm, the thickness of the tab connection 702 is too small, resulting in poor structural strength and making it prone to burn-through during welding with the tab 402, leading to poor stability and reliability of the connection. If h4 is greater than 1 mm, the thickness of the tab connection 702 is too large, resulting in excessive weight, higher cost, and hindering the improvement of internal space utilization within the battery cell. Therefore, by limiting h4 to a value within the range of 0.4 mm to 1 mm, the tab connection 702 has a reasonable thickness. This ensures that the tab connection 702 has sufficient structural strength and prevents it from being welded through during the welding process with the tab 402, thereby improving the reliability of the tab connection 702 and ensuring the stability of the connection between the tab connection 702 and the tab 402. It also controls the weight of the connecting piece 70, reduces costs, and improves the internal space utilization of the battery cell, which is beneficial to improving the energy density of the battery cell.

[0056] In one embodiment, the thickness h3 of the tab 402 is in the range of 0.1 mm ≤ h3 ≤ 1 mm. If h3 is less than 0.1 mm, the tab 402 is too thin and prone to tearing; if h3 is greater than 1 mm, the tab 402 is too thick and too heavy. Therefore, by limiting h3 to the range of 0.1 mm to 1 mm, tearing of the tab 402 can be avoided, ensuring its reliability, while also reducing weight and achieving cell lightweighting.

[0057] Optionally, the value of h3 is any value among 0.1 mm, 0.2 mm, 0.4 mm, 0.5 mm, 0.7 mm, -9 mm, 1 mm, or a value between any two values.

[0058] In one embodiment, further combination Figures 8 to 9 As shown, along the Z direction, the distance between the support member 50 and the electrode assembly body 401 is h5, where the value of h5 ranges from 0 to 5 mm. The support member 50 is an insulating component. When h5 equals 0, the support member 50 is in contact with the first end face 4011 of the electrode assembly body 401. The cover plate assembly applies force to the electrode assembly body 401 through the connection between the first plastic part 30 and the support member 50, further resisting the electrode assembly body 401 and increasing the stability of the battery structure. If h5 is less than 0, the support member 50 will excessively compress the electrode assembly body 401, which may easily damage the electrode assembly body 401. If h5 is greater than 5 mm, the support member 50 is too far from the electrode assembly body 401, the relative stability between the support member 50 and the electrode assembly body 401 is poor, the protective performance of the support member 50 is poor, and it is not conducive to improving the space utilization rate inside the cell. Therefore, by limiting h5 to a value between 0 and 5 mm, it is possible to avoid the support member 50 damaging the electrode assembly body 401, thereby improving the safety of the battery cell. It is also possible to ensure the relative stability between the support member 50 and the electrode assembly body 401, thereby improving the space utilization rate inside the battery cell and thus improving the energy density of the battery cell.

[0059] Optionally, the value of h5 is any one of 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or a value between any two of these values.

[0060] In one embodiment, further combination Figure 3 , Figures 10 to 11As shown, there are two pole groups 40, arranged side-by-side along the Y direction. Each pole group 40 includes a first tab and a second tab 402. There are two support members 50, one corresponding to the two first tabs and the other corresponding to the two second tabs. By using two pole groups 40, and having tabs of the same polarity in both pole groups 40 share one support member 50, the number of support members 50 can be reduced, the internal space utilization of the cell can be improved, and the assembly of the cell can be facilitated.

[0061] In one embodiment, one of the first electrode tab and the second electrode tab is a positive electrode tab and the other is a negative electrode tab. The positive electrode tabs in the two electrode groups 40 are supported by the same support member 50, and the negative electrode tabs in the two electrode groups 40 are supported by another support member 50.

[0062] In one embodiment, there are two connecting pieces 70, with two first tabs connected to the same connecting piece 70 and two second tabs connected to another connecting piece 70.

[0063] In one embodiment, such as Figure 20 As shown, the connecting piece 70 includes a pole post connecting part 701 and a pole tab connecting part 702 connected to each other. The pole tab connecting part 702 is U-shaped and includes a first connecting partition 7021 and a second connecting partition 7022. The first connecting partition 7021 and the second connecting partition 7022 are each connected to a pole tab 402. The first connecting partition 7021 and the second connecting partition 7022 are spaced apart along the Y direction. The gap between the first connecting partition 7021 and the second connecting partition 7022 allows the buckle 302 to pass through. The locking hole 501 is set corresponding to the gap between the first connecting partition 7021 and the second connecting partition 7022 so that the buckle 302 can engage with the locking hole 501.

[0064] In one embodiment, the support member 50 is a support plate with a card hole 501 and a through part 502. The structure is simple, easy to manufacture and process, and easy to assemble in the battery cell. It does not take up too much space and provides good support for the tab 402.

[0065] In one embodiment, the battery cell further includes: an injection hole 201, which is formed on the cover plate body 20 and extends through the cover plate body 20 in the Z direction, for injecting electrolyte into the battery cell; a plug 202 and a cover 203, wherein the plug 202 is detachably plugged into the injection hole 201, and the cover 203 is detachably covered at the opening of the injection hole 201. When it is necessary to inject electrolyte into the battery cell, the plug 202 and the cover 203 are opened. When it is not necessary to inject electrolyte into the battery cell, the plug 202 is inserted into the injection hole 201 and the cover 203 is placed on the injection hole 201 to seal the injection hole 201 and prevent electrolyte leakage.

[0066] In one embodiment, the battery cell further includes an explosion-proof valve 80, which is disposed on the housing 10 or the cover plate body 20. The explosion-proof valve 80 opens when the internal air pressure of the battery cell reaches a certain value, thereby preventing the battery cell from exploding due to excessive internal air pressure and improving safety.

[0067] In one embodiment, the battery cell further includes an insulating film 90, which wraps around the outside of the electrode group 40 to improve the insulation between the electrode group 40 and the housing 10.

[0068] According to an embodiment of the present invention, another aspect provides a battery pack, including the aforementioned battery cells. The battery pack also includes a housing, in which the battery cells are placed.

[0069] Preferably, there are multiple battery cells, and the battery cells are lithium-ion cells.

[0070] 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 battery cell, characterized in that, include: The shell has an open end; A cover plate assembly is disposed at the opening end of the housing. The cover plate assembly includes a cover plate body and a first plastic part. The first plastic part is disposed on the side of the cover plate body facing the inner cavity of the housing. The first plastic part includes a plastic part body and a buckle. The buckle is fixedly connected to the side of the first plastic part away from the cover plate body. The electrode assembly includes an electrode assembly body and an electrode tab. The end of the electrode assembly body facing the cover plate assembly is a first end face. The electrode tab extends from the electrode assembly body and bends toward the first end face. A support member is at least partially disposed between the electrode tab and the first end face. The support member has a locking hole, which is spaced apart from the electrode tab and engages with the buckle.

2. The battery cell according to claim 1, characterized in that, The buckle includes a rod and a head. The rod is connected between the plastic body and the head. The axis of the rod extends along the Z direction. The cross-sectional area of ​​the head in the XY plane is greater than the cross-sectional area of ​​the rod in the XY plane. The locking hole includes a first segment and a second segment. The second segment is connected to the end of the first segment away from the cover plate body. The diameter of the second segment is larger than the diameter of the first segment. The head is locked in the second segment.

3. The battery cell according to claim 2, characterized in that, The dimension of the support member along the Z direction is h, and the dimension of the first hole segment along the Z direction is h1, wherein h1 and h satisfy the relationship: 1 / 3≤h1 / h≤2 / 3.

4. The battery cell according to claim 3, characterized in that, The value range of the dimension h of the support member along the Z direction is: 0.5 mm ≤ h ≤ 5 mm.

5. The battery cell according to claim 1, characterized in that, The support member has a through portion, which is spaced apart from the card hole.

6. The battery cell according to claim 1, characterized in that, The cover plate assembly further includes a terminal post, and the battery cell further includes a connecting piece. The connecting piece includes a terminal post connecting portion and a tab connecting portion. The terminal post connecting portion is electrically connected to the terminal post, and the tab connecting portion is located between the first plastic part and the tab, and the tab connecting portion is electrically connected to the tab.

7. The battery cell according to claim 6, characterized in that, Along the Z direction, the distance between the plastic body and the support is h2, the thickness of the tab is h3, and the thickness of the tab connection is h4, wherein h2, h3 and h4 satisfy the relationship: 0 < h2 - h3 - h4 ≤ 2 mm.

8. The battery cell according to claim 7, characterized in that, The thickness h4 of the electrode connecting part is in the range of 0.4 mm ≤ h4 ≤ 1 mm; And / or, the thickness h3 of the electrode tab is in the range of 0.1 mm ≤ h3 ≤ 1 mm.

9. The battery cell according to claim 1, characterized in that, Along the Z direction, the distance between the support member and the pole group body is h5, where the value of h5 is in the range of 0≤h5≤5 mm; And / or, the number of the pole groups is two, the two pole groups are arranged side by side along the Y direction, each pole group includes a first pole and a second pole, the number of the support members is two, one support member is arranged corresponding to the two first poles, and the other support member is arranged corresponding to the two second poles.

10. A battery pack, characterized in that, include: The battery cell according to any one of claims 1 to 9.

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