Battery and cell cover plate

Abstract

The application relates to a battery cell cover plate, a battery cell and a battery, and belongs to the technical field of batteries, and is used for solving the interface fracture problem caused by stress of a copper-aluminum composite negative pole post. The application forms a first limiting part of the copper part of the negative pole post, which directly bears the rebound force of a sealing ring; an aluminum part forms a second limiting part, which is welded and fixed with a connecting block, so that the first limiting part of the copper part can resist the rebound force of the sealing ring and is transmitted to the copper-aluminum combined interface, and the sealing ring compression rate and the thickness of the first limiting part are controlled through a mathematical model, so that the sealing property is guaranteed and interface tensile stress concentration is avoided, thereby preventing the short circuit or thermal runaway risk caused by the fracture of the pole post.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery cell cover plate and a battery. BACKGROUND

[0002] With the continuous improvement of the requirements for energy density and safety performance in the field of battery technology, a scheme of using copper-aluminum composite material as the negative pole of the battery cell riveting cover plate has appeared. It combines the high conductivity of the copper layer with the lightweight characteristics of the aluminum layer, ensuring electrical conductivity while achieving structural weight reduction, which further leads to the assembly structure centered on the composite pole.

[0003] However, the above technical solution has the following problems:

[0004] When the sealing ring at the bottom of the pole rebounds or the pole bears external impact load, tensile stress exists between the copper layer and the aluminum layer; under high-temperature cycle conditions or overcharge, this stress concentration effect will cause micro-cracks at the composite interface and continue to expand, eventually causing the pole to break along the composite interface, causing internal short circuit of the battery cell or triggering thermal runaway, which seriously threatens the safe operation of the battery system. SUMMARY

[0005] Therefore, it is necessary to provide a battery cell cover plate and a battery to optimize the negative pole structure and solve the problem of easy peeling of the copper layer and the aluminum layer under tensile stress in the prior art.

[0006] A battery cell cover plate, comprising:

[0007] A cover plate body, based on which a thickness direction is defined, the cover plate body is provided with a mounting hole along the thickness direction; the cover plate body includes a first side and a second side, the first side and the second side being two opposite sides of the cover plate body in the thickness direction;

[0008] A connecting block, the connecting block has a stepped hole penetrating through the connecting block along the thickness direction, the stepped hole includes a first hole having a first hole diameter, a second hole having a second hole diameter, and a limiting step formed between the first hole and the second hole, the first hole diameter being greater than the second hole diameter; the connecting block is located on the first side of the cover plate body in the thickness direction, and the second hole is closer to the cover plate body than the first hole;

[0009] The negative pole post comprises a plate body part and a post body part, the post body part comprises a first part integrated with the plate body part and a second part away from the plate body part in the thickness direction and connected to the first part; the plate body part is located on the second side of the cover plate body in the thickness direction; the post body part penetrates the mounting hole and the second hole and extends into the first hole, the post body part is formed with a limiting part on the limiting step, the limiting part comprises a first limiting part formed based on the first part and a second limiting part formed based on the second part;

[0010] The sealing ring is sleeved on the post body part and at least partially clamped between the cover plate body and the plate body part;

[0011] The second limiting part is circumferentially welded and fixed to the inner circumferential wall of the first hole, and the strength of the first limiting part at least offsets the rebound force F of the sealing ring acting on the negative pole post in the thickness direction due to being compressed 回弹 .

[0012] In one embodiment, the first part of the post body part and the plate body part are made of copper, and the second part of the post body part is made of aluminum.

[0013] In one embodiment, the connecting block is made of aluminum.

[0014] In one embodiment, the sealing ring is selected from any one of nitrile rubber, hydrogenated nitrile rubber, fluororubber, silicone rubber, ethylene propylene diene rubber, and chloroprene rubber.

[0015] In one embodiment, the sealing ring is made of fluororubber, the thickness of the compressed part of the sealing ring clamped between the cover plate body and the plate body part and compressed in the thickness direction is a in the relaxed state, the thickness of the compressed part in the compressed state in the battery cell cover plate is b, and the compression amount is , satisfying .

[0016] In one embodiment, the thickness of the first limiting part in the thickness direction is d, satisfying:

[0017]

[0018] wherein, represents the yield strength of copper material;

[0019] D represents the circumference of the orthogonal projection of the second hole on a plane perpendicular to the thickness direction;

[0020] S represents the area of the orthogonal projection of the compressed part on a plane perpendicular to the thickness direction before compression.

[0021] In one embodiment, the width c of the first limiting portion in the radial direction of the pole post satisfies: 0.2mm≤c≤2mm.

[0022] In one embodiment, a first plastic member is further included, extending around the column portion and onto the surface of the cover body near the connecting block, and the first plastic member is at least partially located between the cover body and the connecting block; and / or

[0023] The second plastic part extends around the column portion and onto the surface of the cover plate body near the plate portion, and the second plastic part is at least partially located between the cover plate body and the plate portion.

[0024] In one embodiment, the thickness of the first limiting portion in the thickness direction is d, the thickness of the second limiting portion in the thickness direction is e, and the depth of the first hole in the thickness direction is the sum of the thicknesses of the first limiting portion and the second limiting portion.

[0025] On the other hand, this application also provides a battery, including the aforementioned cell cover.

[0026] The aforementioned cell cover and battery suppress the crack propagation of the composite interface under impact load or when the sealing ring rebounds due to the limiting part, thereby preventing short circuit or thermal runaway caused by the breakage of the terminal post; at the same time, this application limits the thickness of the first limiting part to ensure that the strength of the copper layer is greater than the rebound force of the sealing ring, thereby resisting interface separation.

[0027] This application also has the following advantages:

[0028] This application limits the compression parameters of the sealing ring. The lower limit of the compression ensures airtightness, while the upper limit of the compression prevents the sealing ring from failing due to plastic deformation caused by excessive compression. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of this application.

[0030] Figure 2 for Figure 1 A schematic diagram of the structure under explosive conditions.

[0031] Figure 3 for Figure 1 Sectional view in front view.

[0032] Figure 4 for Figure 3 Enlarged schematic diagram of part A in the diagram.

[0033] Figure 5 for Figure 4 Enlarged schematic diagram of part I in the diagram.

[0034] Figure 6 for Figure 4Enlarged schematic diagram of Part II.

[0035] Figure 7 This is a schematic diagram of the negative electrode post of this application.

[0036] Figure 8 This is a schematic diagram of the connection block structure of this application.

[0037] Figure 9 This is a schematic diagram of the sealing ring of this application.

[0038] Figure 10 This is a schematic diagram showing the mating state of the sealing ring and the cover plate body in this application.

[0039] Figure 11 This is a schematic diagram of the through hole structure of the connecting block in this application.

[0040] Wherein: 100, cover plate body; 200, first plastic part; 300, second plastic part; 400, connecting block; 500, sealing ring; 600, negative terminal post; 700, positive terminal post;

[0041] 101. Mounting holes;

[0042] 410. Stepped hole;

[0043] 411. First hole; 412. Second hole; 413. Limiting step;

[0044] 501. Compression section;

[0045] 600a, Plate section; 600b, Column section;

[0046] G1, Part 1; G2, Part 2;

[0047] G11, First limiting part; G21, Second limiting part. Detailed Implementation

[0048] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0049] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0050] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0053] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0054] See Figures 1-11 The diagram shows a structural schematic of a cell cover plate according to an embodiment of this application.

[0055] This application provides a battery cell cover plate, comprising:

[0056] The cover plate body 100 is defined in the thickness direction, and the cover plate body 100 is provided with mounting holes 101 along the thickness direction; the cover plate body 100 includes a first side and a second side, the first side and the second side being two opposite sides of the cover plate body 100 in the thickness direction.

[0057] like Figure 8 The connecting block 400 shown has a stepped hole 410 extending through the connecting block 400 along the thickness direction. The stepped hole 410 includes a first hole 411 with a first diameter, a second hole 412 with a second diameter, and a limiting step 413 formed between the first hole 411 and the second hole 412. The first diameter is larger than the second diameter. The connecting block 400 is located on a first side of the cover plate body 100 in the thickness direction, and the second hole 412 is located closer to the cover plate body 100 than the first hole 411.

[0058] like Figure 7 The negative electrode post 600 shown includes a plate portion 600a and a post portion 600b. The post portion 600b includes a first portion G1 integral with the plate portion 600a and a second portion G2 that is located away from the plate portion 600a in the thickness direction and is joined to the first portion G1. The plate portion 600a is located on the second side in the thickness direction of the cover plate body 100, and the first side and the second side are two opposite sides in the thickness direction of the cover plate body 100. The post portion 600b passes through the mounting hole 101 and the second hole 412 and extends into the first hole 411. The post portion 600b forms a limiting portion located on the limiting step 413. The limiting portion includes a first limiting portion G11 formed based on the first portion G1 and a second limiting portion G21 formed based on the second portion G2.

[0059] like Figure 9 The sealing ring 500 shown is sleeved on the column part 600b and partially sandwiched between the cover plate body 100 and the plate part 600a.

[0060] The second limiting part G21 is circumferentially welded and fixed to the inner circumferential wall of the first hole 411, and the strength of the first limiting part G11 is sufficient to offset the rebound force F of the sealing ring 500 acting on the negative electrode post 600 due to being compressed in the thickness direction. 回弹 This prevents the first part G1 and the second part G2 from separating.

[0061] By welding the second limiting part G21 circumferentially to the inner circumferential wall of the first hole 411, it can be understood that the welding fixation can be a local point of the second limiting part G21 circumferentially welded to the inner circumferential wall of the first hole 411. The second limiting part G21 is pressed against the first limiting part G11, which can increase the strength of the first limiting part G11 to a certain extent and prevent the first limiting part G11 from deforming; and this welding can also make the interface combination between the first part G1 and the second part G2 a redundant design to offset part of the elastic force of the sealing ring 500; furthermore, the welding fixation can serve as a stable channel for current transmission, avoiding loosening caused by interference fit after long-term use, where impurities may be embedded in the gap or it may be oxidized, resulting in unstable current transmission.

[0062] It is understandable that the above-mentioned welding fixation can also be that the entire circumference of the second limiting part G21 and the inner peripheral wall of the first hole 411 form a welding surface, so that the joint interface between the first part G1 and the second part G2 is in a relatively closed space, further avoiding electrochemical oxidation caused by external impurities at the interface joint.

[0063] In some embodiments, the first part G1 of the column portion 600b and the plate portion 600a are made of copper, and the second part G2 of the column portion 600b is made of aluminum.

[0064] Furthermore, the connecting block 400 is made of aluminum.

[0065] In some embodiments, the thickness of the first limiting part G11 in the thickness direction is d, the thickness of the second limiting part G21 in the thickness direction is e, and the depth of the first hole 411 in the thickness direction is e+d.

[0066] In some embodiments, the sealing ring 500 is selected from any one of nitrile rubber, hydrogenated nitrile rubber, fluororubber, silicone rubber, EPDM rubber, and chloroprene rubber; preferably fluororubber.

[0067] Furthermore, the sealing ring 500 is made of fluororubber. The compression portion 501, which is sandwiched between the cover body 100 and the plate portion 600a and is compressed in the thickness direction, has a thickness of 'a' in the relaxed state. The thickness of the compression portion 501 after being compressed in the cell cover is 'b', and the compression amount is [missing information]. ,satisfy .

[0068] Furthermore, the experimental data for the sealing ring 500 based on compression are shown in Table 1:

[0069] Table 1

[0070]

[0071] Based on Table 1 above, it can be seen that in control group 1, the airtightness is poor when the compression of sealing ring 500 is 0.2 (the compression is less than 0.25 at this time); in control group 2, the compression of sealing ring 500 is too large when the compression is 0.55, and the sealing ring is prone to collapse and failure (the compression is greater than 0.5 at this time).

[0072] See also Figure 4 In some embodiments, the thickness of the first limiting portion G11 in the thickness direction is d, satisfying:

[0073]

[0074] in, Indicates the yield strength of copper.

[0075] like Figure 11 As shown, D represents the perimeter of the second hole 412 as an orthographic projection onto a plane perpendicular to the thickness direction;

[0076] S represents the orthogonal projection area of ​​the compression section 501 on a plane perpendicular to the thickness direction before compression;

[0077] In the above formula, the unit of d is mm;

[0078] In the above formula, the unit of S is mm. 2 ;

[0079] In the above formula, the unit of D is mm;

[0080] In the above formula, The unit is MPa;

[0081] In the above formula, This can be understood as follows: the sealing ring 500 is made of fluororubber. Through actual measurement, the stress and strain values ​​of the sealing ring 500 under different compression amounts (such as 20%, 25%, 30%, 35%, 40%, etc.) are collected. Then, the stress curve equation of the sealing ring 500 is calculated by fitting. This equation represents the rebound stress under a certain compression amount, and the unit is MPa.

[0082] The orthographic projection area S of the compression section 501 on a plane perpendicular to the thickness direction is calculated using the following formula:

[0083] S = π * R1² - π * R2²

[0084] R1 above refers to the outer radius of the sealing ring 500;

[0085] R2 is the inner radius of the sealing ring 500.

[0086] Furthermore, in practical applications, based on the overall contract requirements, the strength of the first limiting part G11 must not be less than 1000N, therefore it must meet the following requirements: ;

[0087] Therefore, the thickness d of the first limiting part G11 in the thickness direction cannot be less than the rebound force generated after the sealing ring 500 is compressed, and at the same time, it cannot be less than the thrust of 1000N (to meet the thrust requirement).

[0088] The experimental data based on the relationship of thickness d are shown in Table 2:

[0089] Table 2

[0090]

[0091] Based on Table 2 above, and substituting the data from control groups 1 to 3 in Table 2 into the above relational analysis, it can be seen that the thickness d cannot simultaneously satisfy...

[0092] and ;

[0093] Therefore, it is impossible to meet the requirement that the pole strength is greater than 500 and the rebound force is greater than 1000N.

[0094] In some embodiments, the width c of the first limiting part G11 in the radial direction of the pole post satisfies: 0.2mm≤c≤2mm.

[0095] Furthermore, experiments were conducted based on the step width c, and the data are shown in Table 3:

[0096] Table 3

[0097]

[0098] Based on Table 3 above, in control group 1, when the step width is 0.15mm, the step characteristics are not obvious, and the negative electrode post 600 is easy to fall off (the step width c in the radial direction of the column structure is less than 0.2mm); in control group 2, when the step width is 2.5mm, the step is too wide, and the electrode post cannot be completely filled with material expansion (the step width c in the radial direction of the column structure is greater than 2mm).

[0099] In practical applications, the sealing ring 500 actually also includes an extension portion extending in the thickness direction. However, because the thickness of the extension portion in the thickness direction is relatively large, the compression amount is calculated... When the denominator is large and the numerator is small, the compressive rebound force of the extension can be ignored compared to the ring part.

[0100] In some embodiments, the cell cover also includes a positive electrode post 700.

[0101] In some embodiments, the cell cover plate further includes a first plastic member 200 and a second plastic member 300, respectively disposed on both sides of the cover plate body 100 in the thickness direction; wherein, the first plastic member 200 extends around the column portion 600b and on the surface of the cover plate body 100 near the connecting block 400, and the first plastic member 200 is at least partially located between the cover plate body 100 and the connecting block 400; the second plastic member 300 extends around the column portion 600b and on the surface of the cover plate body 100 near the plate portion 600a, and the second plastic member 300 is at least partially located between the cover plate body 100 and the plate portion 600a.

[0102] In other embodiments, a battery is also provided, including the aforementioned battery cell.

[0103] In summary, this application uses a limiting part to suppress the crack propagation of the composite interface under impact load or when the sealing ring 500 rebounds, thereby preventing the negative electrode post 600 from breaking and causing a short circuit or thermal runaway. At the same time, this application limits the thickness of the first limiting part G11 to ensure that the strength of the copper layer is greater than the rebound force of the sealing ring 500, thereby resisting interface separation.

[0104] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell cover plate, comprising: A cover plate body, with a thickness direction defined by the cover plate body, and mounting holes provided along the thickness direction; the cover plate body includes a first side and a second side, the first side and the second side being two opposite sides of the cover plate body in the thickness direction; A connecting block having a stepped hole extending through the connecting block along the thickness direction, the stepped hole including a first hole having a first diameter, a second hole having a second diameter, and a limiting step formed between the first hole and the second hole, wherein the first diameter is larger than the second diameter; The connecting block is located on the first side of the thickness direction, and the second hole is located closer to the cover plate body than the first hole; A negative electrode post includes a plate portion and a column portion. The column portion includes a first portion integral with the plate portion and a second portion that is located away from the plate portion in the thickness direction and joined to the first portion. The plate portion is located on a second side in the thickness direction. The column portion passes through the mounting hole and the second hole and extends into the first hole. The column portion forms a limiting portion located on the limiting step. The limiting portion includes a first limiting portion formed based on the first portion and a second limiting portion formed based on the second portion. A sealing ring, which is sleeved on the column portion and at least partially sandwiched between the cover plate body and the plate portion; The second limiting part is welded and fixed to the inner circumferential wall of the first hole in the circumferential direction, and the strength of the first limiting part is sufficient to at least offset the rebound force F of the sealing ring acting on the negative electrode post in the thickness direction due to compression. 回弹 .

2. The cell cover plate according to claim 1, characterized in that, The first part of the column and the plate part are made of copper, and the second part of the column is made of aluminum.

3. The cell cover plate according to claim 2, characterized in that, The sealing ring is selected from any one of nitrile rubber, hydrogenated nitrile rubber, fluororubber, silicone rubber, EPDM rubber, and chloroprene rubber.

4. The cell cover plate according to claim 2, characterized in that, The sealing ring is made of fluororubber. The thickness of the compressed portion, sandwiched between the cover plate body and the plate portion and compressed in the thickness direction, is 'a' in the relaxed state. The thickness of the compressed portion after compression within the cell cover plate is 'b', and the compression amount is [missing information]. ,satisfy .

5. The cell cover plate according to claim 4, characterized in that, The thickness of the first limiting part in the thickness direction is d, which satisfies: in, Indicates the yield strength of copper. D represents the perimeter of the second hole as an orthographic projection onto a plane perpendicular to the thickness direction; S represents the orthogonal projection area of ​​the compressed portion on a plane perpendicular to the thickness direction before compression.

6. The cell cover plate according to claim 5, characterized in that, The width c of the first limiting part in the radial direction of the pole post satisfies: 0.2mm≤c≤2mm.

7. The cell cover plate according to claim 2, characterized in that, The connecting block is made of aluminum.

8. The cell cover plate according to claim 1, characterized in that, Also includes: A first plastic component extends around the column portion and onto the surface of the cover plate body near the connecting block, and the first plastic component is at least partially located between the cover plate body and the connecting block; and / or The second plastic part extends around the column portion and onto the surface of the cover plate body near the plate portion, and the second plastic part is at least partially located between the cover plate body and the plate portion.

9. The cell cover plate according to claim 1, characterized in that, The thickness of the first limiting part in the thickness direction is d, the thickness of the second limiting part in the thickness direction is e, and the depth of the first hole in the thickness direction is the sum of the thicknesses of the first limiting part and the second limiting part.

10. A battery, characterized in that, Includes the cell cover plate according to any one of claims 1-9.

Images