Pole structure, cover plate assembly and battery cell

Abstract

This invention relates to the field of battery technology, and discloses an electrode post structure, a cover plate assembly, and a battery cell. The electrode post structure includes: an electrode post body comprising a plate and a post, the post being fixedly connected to a first side of the plate along its height direction, the surface of the first side of the plate being a first surface, and the dimension of the plate along its height direction being h; a heat insulation layer comprising a first heat insulation portion and a second heat insulation portion, the first heat insulation portion being annular and surrounding the outer periphery of the post, the first heat insulation portion being adhered to the first surface, the dimension of the first heat insulation portion along its height direction being h1, and the second heat insulation portion being connected to the inner ring of the first heat insulation portion and fitted onto the outer periphery of the post; wherein h and h1 satisfy the relationship: [equation missing], and k is a coefficient. By adding a heat insulation layer to the electrode post body, heat transfer can be blocked. The thickness of the first heat insulation portion is inversely proportional to the thickness of the plate, conforming to the heat transfer law and avoiding heat-induced deformation or heat aging of the sealing ring leading to poor sealing.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to electrode structures, cover plate assemblies, and battery cells. Background Technology

[0002] The terminal structure is a crucial component of the battery cell. It, along with the cover plate body, riveting blocks, upper and lower plastic inserts, and sealing rings, are assembled into the cover plate assembly. The terminal structure passes through terminal holes in the cover plate body, and the sealing ring is fitted onto the terminal structure to ensure a tight seal between them. Traditionally, terminal structures are typically cylindrical. Current technologies have transformed cylindrical terminals into racetrack-shaped structures to meet the demands of high current capacity.

[0003] However, since the racetrack-shaped pole needs to withstand a large current, the pole base plate and the electrode tab welding also need to withstand a large current. This results in a larger welding melting area between the electrode tab and the base plate, and a larger welding heat generation. The high temperature generated by welding will be transmitted along the pole to the sealing ring. The sealing ring is easily affected by heat and may be deformed by heat melting or aged by heat, resulting in poor sealing and thus the cell being unqualified. Summary of the Invention

[0004] In view of this, the present invention provides a pole structure, a cover plate assembly, and a battery cell to solve the problem that the welding heat generated by welding the pole structure and the tab can easily be transferred to the sealing ring, resulting in poor sealing.

[0005] In a first aspect, the present invention provides an electrode post structure, comprising: an electrode post body, including a plate and a post, the post being fixedly connected to a first side of the plate along the height direction, the surface of the first side of the plate being a first surface, and the dimension of the plate along the height direction being h; a heat insulation layer, including a first heat insulation portion and a second heat insulation portion, the first heat insulation portion being annular and surrounding the outer periphery of the post, the first heat insulation portion being attached to the first surface, the dimension of the first heat insulation portion along the height direction being h1, the second heat insulation portion being connected to the inner ring of the first heat insulation portion, and the second heat insulation portion being sleeved on the outer periphery of the post; wherein, h and h1 satisfy the following relationship: , where k is a coefficient.

[0006] Beneficial effects: By adding a heat insulation layer to the electrode body, and the heat insulation layer including a first heat insulation part attached to the first surface of the plate and a second heat insulation part sleeved and attached to the electrode body, the heat insulation layer can block the heat generated during the welding process between the electrode body and the electrode tab from being transferred to other components located on the first side of the plate. Furthermore, by setting the thickness h1 of the first heat insulation part to be inversely proportional to the thickness h of the plate, which conforms to the heat transfer law, the thickness of the first heat insulation part can be reasonably set according to the thickness of the plate, thereby effectively avoiding the influence of welding heat on the sealing ring, avoiding the sealing ring from heat melting deformation or heat aging leading to poor sealing, ensuring the sealing reliability of the sealing ring, and ensuring the pass rate of the battery cell.

[0007] In one optional implementation, the value of k is in the range of 0.1≤k≤0.15.

[0008] Beneficial effects: It can ensure that the first heat insulation part has sufficient thickness, thereby ensuring the heat insulation effect of the first heat insulation part, and avoid the waste of materials due to excessive thickness of the first heat insulation part, thus saving costs. When the first heat insulation part is a coating structure, it can prevent the coating from cracking and peeling due to excessive thickness of the first heat insulation part, ensuring the structural stability of the first heat insulation part, which can also ensure its heat insulation effect. This prevents a large amount of heat generated when welding the electrode tab to the plate from being transferred to the sealing ring, causing the sealing ring to melt, deform or age due to heat, thus ensuring the sealing effect.

[0009] In one optional embodiment, the value range of the dimension h of the plate along the height direction is: 0.8 mm ≤ h ≤ 3 mm;

[0010] And / or, the value range of the dimension h1 of the first heat insulation part along the height direction is: 0.05 mm ≤ h1 ≤ 1 mm.

[0011] Beneficial effects: By limiting h to a value between 0.8 mm and 3 mm, it is possible to ensure that the plate has sufficient structural strength and that the electrode body can withstand the required push and pull forces, thereby ensuring the reliability of the electrode body. It also avoids excessive heat transfer from the second side of the plate to the first side, thus avoiding excessive thickness of the first heat insulation part and excessive heat impact on the sealing ring, ensuring sealing performance. Furthermore, it avoids excessive plate thickness leading to excessive weight and excessive occupation of internal space of the battery cell, thereby controlling costs and ensuring that the battery cell has a high energy density.

[0012] And / or, by limiting h1 to a value between 0.05 mm and 1 mm, it is possible to ensure that the first heat insulation part has sufficient heat insulation effect and realize the heat insulation function of the heat insulation layer, while avoiding stress concentration in the coating due to excessive thickness of the first heat insulation part, and avoiding cracks and peeling of the first heat insulation part, thereby ensuring the reliability of the heat insulation layer and further ensuring the heat insulation effect.

[0013] In one optional embodiment, a sealing ring is fitted around the outer periphery of the second heat insulation part, the lower surface of the sealing ring is in contact with the upper surface of the first heat insulation part, the lower surface of the sealing ring is annular with a ring width of W2, and the ring width of the first heat insulation part is W1, wherein W1 is greater than W2.

[0014] Beneficial effects: By setting the lower surface of the sealing ring to fit against the upper surface of the first heat insulation part, and the annular width W1 of the first heat insulation part is greater than the annular width W2 of the lower surface of the sealing ring, direct contact between the sealing ring and the plate is avoided, thereby effectively adding a heat insulation structure between the plate and the sealing ring, reducing the influence of welding heat on the sealing ring, and improving the sealing performance and service life of the sealing ring.

[0015] In one alternative implementation, W1 and W2 satisfy the following relationship: 0.2 mm ≤ W1 - W2 ≤ 0.6 mm;

[0016] And / or, W1 and W2 satisfy the following relationship: 0.8mm≤W2<W1≤3mm.

[0017] Beneficial effects: By limiting W1-W2 to between 0.2 mm and 0.6 mm, it is possible to ensure that the first heat insulation part can provide sufficient heat insulation width, avoid the sealing ring from aging due to heat, thereby improving the sealing performance and service life of the sealing ring, and also avoid wasting materials and saving costs.

[0018] And / or, by limiting the value range of 0.8 mm ≤ W2 < W1 ≤ 3 mm, it is possible to ensure that the sealing ring has sufficient sealing width to guarantee sealing performance, while avoiding excessive ring width of the first heat insulation part and excessive sealing width of the sealing ring, thereby avoiding material waste and saving costs.

[0019] In one optional embodiment, the column includes a rod and a head, the rod being connected between the plate and the head, and the second heat insulation portion being sleeved on the outer periphery of the rod; along the height direction, the total height of the heat insulation layer is H1, the dimension of the rod is H2, and the dimension of the compressed sealing ring is H3, wherein H1, H2, and H3 satisfy the relationship: H3 + h1 ≤ H1 ≤ H2.

[0020] Beneficial effects: By limiting the relationship H3+h1≤H1≤H2, it can be ensured that the heat insulation layer can provide sufficient heat insulation height for the sealing ring along the height direction, thereby ensuring sufficient heat insulation area between the sealing ring and the pole body, effectively reducing the influence of welding heat on the sealing ring, avoiding material waste, and ensuring the flow capacity between the pole body and the riveting block.

[0021] In one optional implementation, the value of H1 is in the range of: 1.5 mm ≤ H1 ≤ 6 mm;

[0022] And / or, the range of H2 is: 2.5 mm ≤ H2 ≤ 6 mm.

[0023] Beneficial effects: Limiting H1 to a value between 1 mm and 6 mm can ensure that the second insulation part can provide sufficient insulation height, thereby ensuring the insulation effect of the insulation layer, effectively reducing the impact of welding heat on the sealing ring, ensuring sealing performance, and avoiding material waste and saving costs.

[0024] And / or, by limiting H2 to a value between 2.5 mm and 6 mm, it is possible to ensure that the rod has sufficient structural strength, thereby ensuring that the strength of the pole body and the cover plate assembly meets the usage requirements, and to avoid the pole body being too large and affecting the overall height of the cover plate assembly, thereby ensuring that the cell has a high volumetric energy density.

[0025] In one alternative embodiment, the heat insulation layer is a coating structure.

[0026] Beneficial effects: The coating structure can be formed by directly coating the surface of the electrode body without additional assembly steps, which is convenient for processing and simple in process. After forming, the coating has good adhesion to the surface of the electrode body, high fit, and is not easy to fall off. It can also effectively block the transfer of heat.

[0027] Secondly, the present invention also provides a cover plate assembly, comprising: a cover plate body having a pole post hole; a riveting block disposed on one side of the cover plate body, the riveting block having a riveting hole corresponding to the pole post hole; the aforementioned pole post structure, wherein the plate body of the pole post structure is located on the side of the cover plate body opposite to the riveting block, and the post body passes through the pole post hole and the riveting hole; and a sealing ring sleeved on the post body. Since the cover plate assembly includes a pole post structure and has the same effect as the pole post structure, it will not be described in detail here.

[0028] Thirdly, the present invention also provides a battery cell, comprising: a housing having an open end; an electrode assembly disposed within the housing; and the aforementioned cover plate assembly, the cover plate assembly covering the open end of the housing. Since the battery cell includes the cover plate assembly and has the same effect as the cover plate assembly, it will not be described further here. Attached Figure Description

[0029] To more clearly illustrate the specific embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the welded structure of the cover plate assembly and the electrode assembly before the improvement.

[0031] Figure 2 This is a schematic diagram of a pole post structure according to an embodiment of the present invention;

[0032] Figure 3 for Figure 2 The front view of the pole structure shown;

[0033] Figure 4 for Figure 3 Enlarged view of part A in the diagram

[0034] Figure 5 for Figure 2 A top view of the pole structure shown;

[0035] Figure 6 This is a schematic diagram of the structure of the pole body according to an embodiment of the present invention;

[0036] Figure 7 for Figure 6 The front view of the pole body shown;

[0037] Figure 8 This is a top view of a cover plate assembly according to an embodiment of the present invention.

[0038] Figure 9 for Figure 8 A cross-sectional view along the CC direction;

[0039] Figure 10 for Figure 9 A magnified view of part B in the diagram;

[0040] Figure 11 for Figure 8 An exploded view of the cover plate assembly shown;

[0041] Figure 12 This is a schematic diagram of the sealing ring according to an embodiment of the present invention;

[0042] Figure 13 for Figure 12 The cross-sectional view of the sealing ring shown.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Pole post body; 110. Plate; 111. First surface; 120. Post; 121. Rod; 122. Head; 2. Insulation layer; 201. First insulation part; 202. Second insulation part; 3. Sealing ring; 301. First ring part; 302. Second ring part; 4. Cover plate body; 401. Pole post hole; 5. Riveting block; 501. Riveting hole; 6. First plastic part; 601. First through hole; 7. Second plastic part; 701. Second through hole; 8. Explosion-proof valve; 9. Explosion-proof patch; 10. Pole assembly; 1001. Pole tab; 1002. Pole tab solder mark. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Lithium-ion batteries are a type of battery. With the increasing maturity of lithium-ion battery technology, they are widely used as power batteries in electric vehicles and energy storage, leading to increasingly stringent requirements for their performance and safety. The cover plate assembly is a key component of a lithium-ion cell, its function being to weld with the casing to form a sealed cavity, to lead out the positive and negative electrodes, and to serve as an assembly carrier, among other things. Figure 1 The diagram shows the positional relationship between the electrode assembly 10 and the electrode post structure in the cover plate assembly before the improvement. The electrode tab 1001 is welded to the plate 110 of the electrode post structure, forming an electrode tab weld mark 1002 on the electrode tab 1001 and the plate 110. For the racetrack-shaped electrode post in the cover plate assembly, since the racetrack-shaped electrode post needs to withstand a large current, the welding of the plate 110 and the electrode tab 1001 must also be able to withstand a large current. This results in a larger welding melting area between the electrode tab 1001 and the plate 110, and a larger welding heat generation. The high temperature generated by the welding will be transmitted along the electrode post to the sealing ring 3. The sealing ring 3 is affected by a large amount of welding heat, which can easily cause it to melt and deform or age due to heat, resulting in poor sealing or even failure, and thus the sealing performance of the battery cell is unqualified.

[0047] The following is combined Figures 2 to 13 The following describes embodiments of the present invention.

[0048] According to an embodiment of the present invention, in one aspect, a pole post structure is provided, such as... Figures 2 to 7As shown, it includes: an electrode body 1 and a heat insulation layer 2. The electrode body 1 includes a plate 110 and a column 120. The column 120 is fixedly connected to the first side of the plate 110 along the height direction. The surface of the first side of the plate 110 is the first surface 111, and the dimension of the plate 110 along the height direction is h. The heat insulation layer 2 includes a first heat insulation part 201 and a second heat insulation part 202. The first heat insulation part 201 is annular and surrounds the outer periphery of the column 120. The first heat insulation part 201 is attached to the first surface 111, and the dimension of the first heat insulation part 201 along the height direction is h1. The second heat insulation part 202 is connected to the inner ring of the first heat insulation part 201 and is sleeved on the outer periphery of the column 120. The relationship between h and h1 is: , where k is a coefficient. The units for h and h1 are both mm.

[0049] It should be noted that the height direction refers to... Figure 3 and Figure 7 The "height direction" indicated by the middle arrow refers to the thickness of the plate 110 along its height direction, and the thickness of the first heat insulation part 201 along its height direction. The inner ring of the first heat insulation part 201 refers to the circumferential edge of the annular part 201 near its center. The second heat insulation part 202 is cylindrical. The plate 110 has a first side and a second side arranged opposite each other along its height direction. A column 120 is connected to the first side of the plate 110, and the second side is used for welding to the tab 1001 of the electrode assembly 10. The welding heat generated during welding with the pole body 1 is transmitted along the height direction from the second side of the plate 110 to the first side. The traditional sealing ring 3 is set on the first side of the plate 110 and directly sleeved on the outer periphery of the pole 120, which is easily affected by welding heat. The relationship between h and h1 in this embodiment conforms to the heat transfer law. According to the basic formula of heat conduction, under the same conditions, heat transfer is inversely proportional to distance. Therefore, the greater the thickness of the plate 110, the less heat is transferred from the second side of the plate 110 to the first side, and the smaller the required thickness of the first heat insulation part 201.

[0050] By applying the electrode post structure of this embodiment, a heat insulation layer 2 is added to the electrode post body 1. The heat insulation layer 2 includes a first heat insulation part 201 attached to the first surface 111 of the plate 110 and a second heat insulation part 202 sleeved and attached to the post body 120. The heat insulation layer 2 can block the heat generated during the welding process between the electrode post body 1 and the electrode tab 1001 from being transferred to other components on the first side of the plate 110. Furthermore, by setting the thickness h1 of the first heat insulation part 201 to be inversely proportional to the thickness h of the plate 110, which conforms to the heat transfer law, the thickness of the first heat insulation part 201 can be reasonably set according to the thickness of the plate 110. This effectively avoids the influence of welding heat on the sealing ring 3, prevents the sealing ring 3 from being deformed by heat or aged by heat, thus ensuring the sealing reliability of the sealing ring 3 and the pass rate of the battery cell.

[0051] In one embodiment, the heat insulation layer 2 is a coating structure. The coating structure can be formed by directly coating it onto the surface of the pole body 1 without additional assembly steps, which is convenient for processing and has a simple process. After forming, it has good adhesion and high fit on the surface of the pole body 1, is not easy to fall off, and can effectively block the transfer of heat.

[0052] Preferably, the heat insulation layer 2 is a spray coating, which is simple to operate and easy to form.

[0053] In one embodiment, the insulation layer 2 is made of a ceramic coating such as alumina (Al2O3) or zirconium oxide (ZrO2), which has good low thermal conductivity and high temperature resistance.

[0054] In one embodiment, the value of k ranges from 0.1 to 0.15. It should be noted that k is a coefficient without units. The dimension h1 of the first heat insulation part 201 along the height direction is inversely proportional to the dimension h of the plate 110 along the height direction. The thicker the plate 110, the smaller the thickness of the first heat insulation part 201. k is an inverse proportionality coefficient. If k < 0.1, the thickness of the first heat insulation part 201 may be insufficient, resulting in poor heat insulation. The heat generated by welding the pole body 1 and the tab 1001 may still be largely transferred to the sealing ring 3, causing the sealing ring 3 to deform due to heat or age due to heat, leading to poor sealing. If k > 0.15, the thickness of the first heat insulation part 201 is too large, wasting material. Furthermore, when the first heat insulation part 201 is a coating structure, excessive thickness can cause the coating structure to crack and peel off, making the coating surface easily damaged. This will also damage the heat insulation effect of the first heat insulation part 201, leading to the welding heat being transferred to the sealing ring 3, causing the sealing ring 3 to melt and deform, affecting the sealing effect.

[0055] Therefore, by limiting k to a value between 0.1 and 0.15, it is possible to ensure that the first heat insulation part 201 has sufficient thickness, thereby ensuring the heat insulation effect of the first heat insulation part 201, while avoiding excessive thickness of the first heat insulation part 201 and thus saving materials and costs. Furthermore, when the first heat insulation part 201 is a coating structure, it is possible to avoid excessive thickness of the first heat insulation part 201, which could lead to cracking and peeling of the coating, thus ensuring the structural stability of the first heat insulation part 201 and its heat insulation effect. This also prevents a large amount of heat generated when welding the tab 1001 to the plate 110 from being transferred to the sealing ring 3, which could cause the sealing ring 3 to melt, deform, or age due to heat, thereby ensuring the sealing effect.

[0056] Optionally, the value of k is any one of 0.1, 0.11, 0.12, 0.13, 0.14, 0.15 or a value between any two values.

[0057] In one embodiment, the dimension h of the plate 110 along the height direction ranges from 0.8 mm to 3 mm. It should be noted that the terminal structure, as an important component of the battery, needs to withstand a certain degree of push-pull force without damage, loosening, or poor contact, to ensure the electrical connection reliability and mechanical stability of the battery during use. If h < 0.8 mm, the thickness of the plate 110 is too small, resulting in insufficient structural strength and insufficient push-pull force that the terminal body 1 can withstand. Furthermore, excessive heat is transferred from the second side of the plate 110 to the first side, significantly impacting the thermal effect on the sealing ring 3. Correspondingly, the thickness of the first heat insulation part 201 needs to be too large, easily leading to coating cracking and peeling. If h > 3 mm, the thickness of the plate 110 is too large, resulting in excessive weight of the terminal body 1, increased cost, and excessive occupation of internal cell space, affecting the overall energy density of the cell.

[0058] Therefore, by limiting h to a value between 0.8 mm and 3 mm, it is possible to ensure that the plate 110 has sufficient structural strength, that the electrode body 1 can withstand the required push and pull forces, thereby ensuring the reliability of the electrode body 1, and to avoid excessive heat transfer from the second side of the plate 110 to the first side, thereby avoiding excessive thickness of the first heat insulation part 201 and excessive heat impact on the sealing ring 3, thus ensuring sealing performance. It is also possible to avoid excessive thickness of the plate 110, which would result in excessive weight and excessive occupation of internal space of the battery cell, thereby controlling costs and ensuring that the battery cell has a high energy density.

[0059] Optionally, the value of h is any one of 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, or a value between any two of these values.

[0060] In one embodiment, the dimension h1 of the first heat insulation portion 201 along the height direction ranges from 0.05 mm to 1 mm. If h1 is less than 0.05 mm, the heat insulation function is limited; if h1 is greater than 1 mm, the thickness of the first heat insulation portion 201 is too large, and an excessively thick coating may lead to stress concentration, cracking, or even peeling. Therefore, by limiting h1 to a value between 0.05 mm and 1 mm, it is possible to ensure that the first heat insulation portion 201 has sufficient heat insulation effect to achieve the heat insulation function of the heat insulation layer 2, while avoiding stress concentration in the coating due to excessive thickness of the first heat insulation portion 201, thus preventing cracking and peeling of the first heat insulation portion 201, thereby ensuring the reliability of the heat insulation layer 2 and further guaranteeing the heat insulation effect.

[0061] Optionally, the value of h1 is any one of 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 1 mm, or a value between any two of these values.

[0062] The following examples illustrate the effect of different values ​​of k on the performance of the pole structure. The test results of the embodiments and comparative examples are shown in Tables 1 to 3. The pole structure of the embodiments satisfies the relationship 0.1≤k≤0.15; the pole structure of the comparative examples does not satisfy the relationship 0.1≤k≤0.15.

[0063] Case 1: The dimension h of the plate 110 along the height direction is 1 mm. Different values ​​of the coefficient k are used to calculate different values ​​of h1 (the dimension of the first heat insulation part 201 along the height direction). The corresponding pole structures with different h1 values ​​are used to assemble a cover plate assembly. The leakage rate of the cover plate assembly after welding the plate 110 and the tab 1001 in different embodiments and comparative examples is measured (leakage rate required ≤ 1 × 10⁻⁶). -7 Pa.m 3 / s), the results are shown in Table 1.

[0064] Table 1

[0065]

[0066] Case 2: The dimension h of the plate 110 along the height direction is 1.5mm. Different values ​​of the coefficient k are used to calculate different values ​​of h1 (the dimension of the first heat insulation part 201 along the height direction). The corresponding pole structures with different h1 values ​​are used to assemble a cover plate assembly. The leakage rate of the cover plate assembly after welding the plate 110 and the tab 1001 in different embodiments and comparative examples is measured (leakage rate required ≤1×10). -7 Pa.m 3 / s), the results are shown in Table 2.

[0067] Table 2

[0068]

[0069] Case 3: The dimension h of the plate 110 along the height direction is 1.8 mm. Different values ​​of the coefficient k are used to calculate different values ​​of h1 (the dimension of the first heat insulation part 201 along the height direction). The corresponding pole structures with different h1 values ​​are used to assemble a cover plate assembly. The leakage rate of the cover plate assembly after welding the plate 110 and the tab 1001 in different embodiments and comparative examples is measured (leakage rate required ≤ 1 × 10⁻⁶). -7 Pa.m 3 / s), the results are shown in Table 3.

[0070] Table 3

[0071]

[0072] As can be seen from Tables 1 to 3, in Examples 1-1 to 1-5, Examples 2-1 to 2-5, and Examples 3-1 to 3-5, the value of k is within the range of 0.1 to 0.15 as defined in this application, and the leakage rate of the cover plate assembly is less than or equal to 1×10⁻⁶. -7 Pa.m 3 / s, which meets the requirements; however, in Comparative Examples 1-1 to 1-3, 2-1 to 2-3, and 3-1 to 3-3, the value of k is less than 0.1, which is outside the range limited by this application, and the leakage rate of the cover plate assembly is greater than 1×10 -7 Pa.m 3 / s, which does not meet the requirements; in Comparative Examples 1-4 to 1-6, 2-4 to 2-6, and 3-4 to 3-6, the value of k is greater than 0.15, which is outside the range limited by this application, and the leakage rate of the cover plate assembly is greater than 1×10 -7 Pa.m 3 / s does not meet the requirements.

[0073] In summary, when h and h1 satisfy the following relationship: When k is in the range of 0.1 to 0.15, the cover plate assembly of the battery cell composed of this pole structure meets the leakage rate requirement, indicating that the sealing ring 3 has not been heat-melted and has the best spraying thickness effect of the corresponding heat insulation layer 2.

[0074] In one embodiment, further combination Figure 9 and Figure 10As shown, a sealing ring 3 is fitted onto the outer periphery of the second heat insulation part 202. The lower surface of the sealing ring 3 is in contact with the upper surface of the first heat insulation part 201. The lower surface of the sealing ring 3 is annular with a ring width of W2, and the ring width of the first heat insulation part 201 is W1, wherein W1 is greater than W2. The lower surface of the sealing ring 3 refers to the surface of the sealing ring 3 facing the plate 110 along the height direction; that is, the lower surface refers to the surface along the... Figure 10 The surface in the direction indicated by the middle arrow "down"; the upper surface of the first heat insulation part 201 refers to the surface of the first heat insulation part 201 facing away from the plate 110 along the height direction, that is, the upper surface refers to the surface along the direction indicated by the middle arrow. Figure 10 The surface in the direction indicated by the middle arrow. By setting the lower surface of the sealing ring 3 to fit against the upper surface of the first heat insulation part 201, and the annular width W1 of the first heat insulation part 201 being greater than the annular width W2 of the lower surface of the sealing ring 3, direct contact between the sealing ring 3 and the plate 110 is avoided. This effectively adds a heat insulation structure between the plate 110 and the sealing ring 3, reduces the influence of welding heat on the sealing ring 3, and improves the sealing performance and service life of the sealing ring 3.

[0075] Further integration Figure 10 and Figures 12 to 13 As shown, the sealing ring 3 includes a first ring portion 301 and a second ring portion 302. The first ring portion 301 is connected to the outer periphery of the second ring portion 302, and the lower surface of the first ring portion 301 is flush with the lower surface of the second ring portion 302. The upper surface of the first ring portion 301 is lower than the upper surface of the second ring portion 302. The second ring portion 302 is sleeved on the outer periphery of the rod portion 121. The first ring portion 301 is compressed between the cover plate body 4 and the plate body 110 to ensure sealing. The upper surface refers to... Figure 10 and Figure 13 The surface indicated by the middle arrow pointing "up" is the surface in the direction of the arrow; the surface below it is the surface in the direction of the arrow pointing "down". Figure 10 and Figure 13 The surface in the direction indicated by the middle arrow "down"; the outer periphery of the second ring 302 refers to the side of the second ring 302 that is away from its axis along a direction perpendicular to its axis; the division between the first ring 301 and the second ring 302 is as follows: Figure 13 As shown by the dashed line, it should be noted that the dashed line is only for illustration and does not actually exist. In fact, the first ring portion 301 and the second ring portion 302 of the sealing ring 3 are integrally formed.

[0076] It should be noted that the annular width W2 of the lower surface of the sealing ring 3 is equal to the sum of the annular width of the first ring portion 301 and the annular width of the second ring portion 302. The area on the sealing ring 3 located between the plate body 110 and the cover plate body 4 is the main sealing area. By setting this area to be located on the side of the first heat insulation portion 201 away from the plate body 110, and W1 being greater than W2, the first heat insulation portion 201 extends beyond the sealing ring 3 along the annular width direction, which can reduce the impact of high temperature on the main sealing area of ​​the sealing ring 3, thereby improving the sealing performance.

[0077] It should be noted that the sealing ring 3 has a free state before assembly and a compressed state after assembly. When the sealing ring 3 is assembled into a cover plate assembly, it is in a compressed state. The dimension of the sealing ring 3 along the height direction is compressed and becomes smaller, while the ring width along the direction perpendicular to the height direction is larger than before compression. The lower surface of the sealing ring 3 after compression is annular and the ring width is W2. That is, W2 is the total ring width of the sealing ring 3 after being compressed when assembled in the cover plate assembly.

[0078] In one embodiment, W1 and W2 satisfy the relationship: 0.2 mm ≤ W1 - W2 ≤ 0.6 mm. It should be noted that if W1 - W2 < 0.2 mm, the width of the first heat insulation portion 201 extending beyond the sealing ring 3 is too small, and the outer ring of the first ring portion 301 of the sealing ring 3 is still easily affected by the heat on the plate 110. That is, the heat insulation width provided by the first heat insulation portion 201 is insufficient, leading to heat aging of the sealing ring 3 and affecting its lifespan. If W1 - W2 > 0.6 mm, the width of the first heat insulation portion 201 extending beyond the sealing ring 3 is too large, resulting in an excessively wide ring of the first heat insulation portion 201 and increased cost. Therefore, by limiting W1 - W2 to a value between 0.2 mm and 0.6 mm, it is possible to ensure that the first heat insulation portion 201 provides sufficient heat insulation width, preventing heat aging of the sealing ring 3, thereby improving the sealing performance and lifespan of the sealing ring 3, while also avoiding material waste and saving costs.

[0079] In one embodiment, W1 and W2 satisfy the relationship: 0.8 mm ≤ W2 < W1 ≤ 3 mm. If W2 < 0.8 mm, the sealing width of the sealing ring 3 is insufficient, resulting in a decrease in sealing performance; if W1 > 3 mm, the annular width of the first heat insulation part 201 is too large, wasting material, and the sealing area of ​​the sealing ring 3 is redundant, occupying internal space of the cover plate and increasing costs. Therefore, by limiting the value range of 0.8 mm ≤ W2 < W1 ≤ 3 mm, it is possible to ensure that the sealing ring 3 has sufficient sealing width to guarantee sealing performance, while avoiding excessive annular width of the first heat insulation part 201 and excessive sealing width of the sealing ring 3, thereby avoiding material waste and saving costs.

[0080] In one embodiment, further combination Figures 6 to 7As shown, the column 120 includes a rod 121 and a head 122. The rod 121 connects the plate 110 and the head 122, further combining... Figures 2 to 4 and Figure 10 As shown, the second heat insulation part 202 is sleeved on the outer periphery of the rod part 121; along the height direction, the total height of the heat insulation layer 2 is H1, the size of the rod part 121 is H2, and the size of the sealing ring 3 after compression is H3. Among them, H1, H2, and H3 satisfy the relationship: H3+h1≤H1≤H2, and the units of H1, H2, and H3 are all mm. It should be noted that the sealing ring 3 is compressed between the first plastic part 6 and the first heat insulation part 201. H3 is equal to the distance between the surface of the first plastic part 6 that abuts against the upper surface of the second ring part 302 of the sealing ring 3 and the upper surface of the first heat insulation part 201. H1 is equal to the dimension of the second heat insulation part 202 of the heat insulation layer 2 along the height direction, that is, the distance between the upper surface of the second heat insulation part 202 and the first surface 111 of the plate 110. H2 is equal to the distance between the lower surface of the riveting block 5 and the plate 110. The distance between the lower surface of the sealing ring 3 and the first surface 111 of the plate 110 is equal to h1.

[0081] It should be noted that the sealing ring 3 is located on the outer periphery of the rod 121, and the upper surface of the sealing ring 3 will not exceed the upper end face of the rod 121. Therefore, the second heat insulation part 202 does not need to extend beyond the rod 121 in the height direction, i.e., H1 is less than or equal to H2. If H1 is greater than H2, it wastes material, and the second heat insulation part 202 extends between the head 122 and the rivet block 5, affecting the conductivity between the head 122 and the rivet block 5, thereby affecting the current flow capacity between the pole body 1 and the rivet block 5. If H1 < H3 + h1, the dimension of the second heat insulation part 202 in the height direction is less than the sum of the total height of the compressed sealing ring 3 and the thickness of the first heat insulation part 201, making the upper surface of the second heat insulation part 202 lower than the upper surface of the sealing ring 3. The heat insulation area provided by the second heat insulation part 202 is insufficient, and the heat from welding the plate 110 and the tab 1001 is transferred to the sealing ring 3 through the rod 121, affecting the sealing performance and lifespan of the sealing ring 3. Here, the upper surface refers to... Figure 10 The surface indicated by the middle arrow pointing "up" is the surface in the direction of the arrow; the surface below refers to... Figure 10 The surface in the direction indicated by the middle arrow, which points to "down".

[0082] Therefore, by limiting the relationship H3+h1≤H1≤H2, it can be ensured that the heat insulation layer 2 can provide sufficient heat insulation height for the sealing ring 3 along the height direction, thereby ensuring that there is sufficient heat insulation area between the sealing ring 3 and the pole body, effectively reducing the influence of welding heat on the sealing ring 3, avoiding material waste, and ensuring the flow capacity between the pole body 1 and the riveting block.

[0083] It should be noted that by setting the first heat insulation part 201 of the heat insulation layer 2 between the first surface 111 of the plate 110 and the lower surface of the sealing ring 3, and the second heat insulation part 202 between the outer peripheral surface of the rod 121 and the inner peripheral surface of the sealing ring 3, a heat insulation layer is added at the mating surface between the pole body 1 and the sealing ring 3, thereby effectively achieving the heat insulation effect between the pole body 1 and the sealing ring 3. The head 122 of the pole 120 passes through the riveting hole 501 on the riveting block 5 and is riveted to the riveting block 5, and the rod 121 is supported between the riveting block 5 and the plate 110.

[0084] In one embodiment, the value of H1 is in the range of 1.5 mm ≤ H1 ≤ 6 mm. If H1 < 1.5 mm, the dimension of the second heat insulation part 202 along the height direction is too small, which cannot ensure that the upper surface of the second heat insulation part 202 is higher than the upper surface of the sealing ring 3. This can easily lead to direct contact between the sealing ring 3 and the column 120, and the contact area is too large. The second ring part 302 of the sealing ring 3 will be greatly affected by heat, resulting in aging or even melting, which will affect the sealing function of the sealing ring 3. If H1 is greater than 6 mm, the dimension of the second heat insulation part 202 along the height direction is too large, exceeding the range of the sealing ring 3, which wastes material. Therefore, by limiting the value of H1 to between 1 mm and 6 mm, it can be ensured that the second heat insulation part 202 can provide sufficient heat insulation height, thereby ensuring the heat insulation effect of the heat insulation layer 2, effectively reducing the impact of welding heat on the sealing ring 3, ensuring sealing performance, and avoiding material waste and saving costs.

[0085] In one embodiment, the value of H2 is in the range of 2.5 mm ≤ H2 ≤ 6 mm. If H2 < 2.5 mm, the height of the rod 121 is too small, resulting in insufficient structural strength and the cover assembly's strength failing to meet usage requirements. If H2 > 6 mm, the height of the rod 121 is too large, leading to an excessively large overall dimension of the cover assembly along the height direction, resulting in an excessively large overall volume of the cover assembly, failing to meet requirements, and insufficient volumetric energy density of the battery cell. Therefore, by limiting H2 to a value between 2.5 mm and 6 mm, it is possible to ensure that the rod 121 has sufficient structural strength, thereby ensuring that the strength of the electrode body 1 and the cover assembly meets usage requirements, while also preventing the height of the electrode body 1 from being too large and affecting the overall height of the cover assembly, thus ensuring that the battery cell has a high volumetric energy density.

[0086] According to an embodiment of the present invention, in another aspect, a cover plate assembly is also provided, such as... Figures 8 to 13As shown, the cover plate assembly includes: a cover plate body 4, a riveting block 5, the aforementioned pole structure, and a sealing ring 3. The cover plate body 4 has a pole hole 401; the riveting block 5 is disposed on one side of the cover plate body 4, and has a riveting hole 501 corresponding to the pole hole 401; the plate 110 of the pole structure is located on the side of the cover plate body 4 away from the riveting block 5, and the pole 120 passes through the pole hole 401 and the riveting hole 501; the sealing ring 3 is fitted onto the pole 120. Specifically, the sealing ring 3 is fitted onto the outer periphery of the rod portion 121 of the pole 120, and is located between the heat insulation layer 2 on the pole body 1 and the cover plate body 4.

[0087] In this embodiment, the cover plate assembly has a heat-insulating coating added to a local area of ​​the electrode body 1 (and the mating surface of the sealing ring 3) to improve the effect of the high temperature generated when the electrode tab 1001 is welded to the electrode structure on the sealing ring 3. This can effectively prevent the sealing ring 3 from melting, deforming or aging due to heat, thus ensuring the sealing performance of the sealing ring 3 and improving the pass rate of the battery cell.

[0088] In one embodiment, the cover plate assembly further includes: a first plastic part 6 and a second plastic part 7. The first plastic part 6 is disposed between the riveting block 5 and the cover plate body 4 to ensure the insulation between the riveting block 5 and the cover plate body 4. The first plastic part 6 has a first through hole 601 corresponding to the pole hole 401. A portion of the rod 121 of the column 120 near the head 122 passes through the first through hole 601. The second plastic part 7 is disposed on the side of the cover plate body 4 away from the first plastic part 6. The second plastic part 7 has a second through hole 701. A portion of the rod 121 of the column 120 near the plate 110 passes through the second through hole 701. The plate 110 is located on the side of the second plastic part 7 away from the cover plate body 4. The plate 110 presses the second plastic part 7 against the cover plate body 4. The second plastic part 7 is used to ensure the insulation between the cover plate body 4 and the pole group.

[0089] In one embodiment, the first plastic part 6 is the upper plastic part, and the second plastic part 7 is the lower plastic part.

[0090] In one embodiment, the cover assembly further includes an explosion-proof valve 8, and the cover body 4 is provided with an explosion-proof valve hole. The explosion-proof valve 8 is disposed in the explosion-proof valve hole. The explosion-proof valve 8 is adapted to open when the gas pressure inside the battery reaches a preset value, so as to timely discharge the high-temperature smoke in the battery and prevent the battery from exploding. An explosion-proof patch 9 is attached to the explosion-proof valve 8 to protect the explosion-proof valve.

[0091] According to an embodiment of the present invention, in another aspect, a battery cell is also provided, comprising: a housing, an electrode assembly, and the aforementioned cover assembly. The housing has an open end; the electrode assembly is disposed within the housing; and the cover assembly covers the open end of the housing. Preferably, the battery is a lithium battery, used in fields such as electric vehicles and energy storage.

[0092] Although embodiments of the 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 invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A pole post structure, characterized in that, include: The pole body includes a plate and a column, the column being fixedly connected to a first side of the plate along the height direction, the surface of the first side of the plate being a first surface, and the dimension of the plate along the height direction being h; The heat insulation layer includes a first heat insulation part and a second heat insulation part. The first heat insulation part is annular and surrounds the outer periphery of the column. The first heat insulation part is attached to the first surface. The dimension of the first heat insulation part along the height direction is h1. The second heat insulation part is connected to the inner ring of the first heat insulation part and is sleeved on the outer periphery of the column. Where h and h1 satisfy the following relationship: k is a coefficient; The value range of k is: 0.1≤k≤0.15; the value range of h of the plate along the height direction is: 0.8 mm≤h≤3 mm; the value range of h1 of the first heat insulation part along the height direction is: 0.05 mm≤h1≤1 mm.

2. The pole post structure according to claim 1, characterized in that, The outer periphery of the second heat insulation part is adapted to be fitted with a sealing ring. The lower surface of the sealing ring is in contact with the upper surface of the first heat insulation part. The lower surface of the sealing ring is annular with a ring width of W2. The ring width of the first heat insulation part is W1, wherein W1 is greater than W2.

3. The pole post structure according to claim 2, characterized in that, The relationship between W1 and W2 is: 0.2 mm ≤ W1 - W2 ≤ 0.6 mm; And / or, W1 and W2 satisfy the following relationship: 0.8mm≤W2<W1≤3mm.

4. The pole post structure according to claim 2, characterized in that, The column includes a rod and a head, the rod being connected between the plate and the head, and the second heat insulation part being sleeved on the outer periphery of the rod; Along the height direction, the total height of the insulation layer is H1, the size of the rod is H2, and the size of the compressed sealing ring is H3, wherein H1, H2, and H3 satisfy the relationship: H3 + h1 ≤ H1 ≤ H2.

5. The pole post structure according to claim 4, characterized in that, The value range of H1 is: 1.5 mm ≤ H1 ≤ 6 mm; And / or, the range of H2 is: 2.5 mm ≤ H2 ≤ 6 mm.

6. The pole post structure according to any one of claims 1 to 5, characterized in that, The heat insulation layer has a coating structure.

7. A cover plate assembly, characterized in that, include: The cover plate body has pole hole; A riveting block is provided on one side of the cover plate body, and the riveting block has a riveting hole corresponding to the pole hole; The pole post structure according to any one of claims 1 to 6, wherein the plate of the pole post structure is located on the side of the cover plate body opposite to the riveting block, and the post is inserted through the pole post hole and the riveting hole; A sealing ring is fitted onto the column.

8. A battery cell, characterized in that, include: The shell has an open end; The electrode assembly is disposed within the housing; The cover assembly of claim 7, wherein the cover assembly covers the opening end of the housing.

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