Pole structure, cover plate assembly and battery cell

Abstract

The invention relates to the technical field of batteries, and discloses a pole structure, a cover plate assembly and a battery cell. The pole structure comprises a pole body, the pole body comprises a plate body and a pole body, the pole body is fixedly connected to the first side of the plate body in the height direction, the surface of the first side of the plate body is a first surface, and the size of the plate body in the height direction is h; the heat insulation layer comprises a first heat insulation part and a second heat insulation part, the first heat insulation part is annular and surrounds the peripheral side of the column body, the first heat insulation part is attached to the first surface, the size of the first heat insulation part in the height direction is h1, the second heat insulation part is connected with an inner ring of the first heat insulation part, and the second heat insulation part is arranged on the peripheral face of the column body in a sleeving mode; wherein h and h1 meet the relational expression: k is a coefficient. The heat insulation layer is additionally arranged on the pole body, heat transfer can be blocked, the thickness of the first heat insulation part is inversely proportional to the thickness of the plate body, the heat transfer rule is met, and poor sealing caused by hot melting deformation or heated aging of the sealing ring is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a pole structure, a cover plate assembly and a battery cell. Background Art

[0002] The pole structure is a critical component of the battery cell. It is assembled with the cover plate, rivet block, upper and lower plastics, and sealing ring to form the cover plate assembly. The pole structure is inserted into the pole hole in the cover plate, and the sealing ring is fitted over the pole structure to ensure a tight seal between the pole structure and the cover plate. Traditional pole structures are typically cylindrical. Existing technologies have transformed cylindrical poles into racetrack-shaped pole structures to meet high current requirements.

[0003] However, since the runway-type pole needs to withstand a large current, the welding of the pole base plate and the pole ear must also be able to withstand a large current, which makes the welding melting area of ​​the pole ear and base plate larger, and the welding heat generation is large. The high temperature generated by the welding will be transmitted along the pole to the sealing ring. The sealing ring is easily affected by the heat and deformed by heat or aged by heat, resulting in poor sealing, and then causing the battery cell to fail. 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 is easily transferred to the sealing ring, resulting in poor sealing.

[0005] In a first aspect, the present invention provides a pole structure, comprising: a pole body, comprising a plate and a column, the column being fixedly connected to a first side of the plate in a height direction, the surface of the first side of the plate being a first surface, and the dimension of the plate in the height direction being h; a heat insulating layer, comprising a first heat insulating portion and a second heat insulating portion, the first heat insulating portion being annular and surrounding the outer circumference of the column, the first heat insulating portion being attached to the first surface, the dimension of the first heat insulating portion in the height direction being h1, the second heat insulating portion being connected to the inner ring of the first heat insulating portion, and the second heat insulating portion being sleeved on the outer circumference of the column; wherein the relationship between h and h1 satisfies the following equation: , k is the coefficient.

[0006] Beneficial effect: By adding a thermal insulation layer to the pole body, and the thermal insulation layer includes a first thermal insulation part attached to the first surface of the plate body, and a second thermal insulation part sleeved on the pole body, the thermal insulation layer can block the heat generated during the welding process of the pole body and the pole ear from being transferred to other components arranged on the first side of the plate body, and by setting the thickness h1 of the first thermal insulation part to be inversely proportional to the thickness h of the plate body, which conforms to the law of heat transfer, the thickness of the first thermal insulation part can be reasonably set according to the thickness of the plate body, thereby effectively avoiding the influence of welding heat on the sealing ring, avoiding the sealing ring from being deformed by heat or aging due to heat, ensuring the sealing reliability of the sealing ring, and ensuring the qualified rate of the battery cell.

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

[0008] Beneficial effects: It can ensure that the first thermal insulation part has sufficient thickness, thereby ensuring the thermal insulation effect of the first thermal insulation part, and can avoid the waste of materials due to the excessive thickness of the first thermal insulation part, which can save costs. When the first thermal insulation part is a coating structure, it can avoid the first thermal insulation part being too thick and causing the coating to crack and peel off, thereby ensuring the structural stability of the first thermal insulation part and also ensuring its thermal insulation effect, thereby avoiding the large amount of heat generated during the welding of the tab and the plate body being transferred to the sealing ring, causing the sealing ring to melt and deform or age due to heat, thereby ensuring the sealing effect.

[0009] In an optional embodiment, the dimension h of the plate body along the height direction is in the range of: 0.8 mm ≤ h ≤ 3 mm; And / or, the dimension h1 of the first heat insulating portion along the height direction has a value range of: 0.05 mm≤h1≤1 mm.

[0010] Beneficial effects: By limiting the value of h to between 0.8 mm and 3 mm, it is possible to ensure that the plate body has sufficient structural strength and that the push and pull forces that the pole body can withstand meet the requirements, thereby ensuring the reliability of the pole body, and to avoid excessive heat transfer from the second side of the plate body to the first side, thereby avoiding excessive thickness of the first heat insulating portion, avoiding excessive thermal impact on the sealing ring, and ensuring sealing performance. It is also possible to avoid excessive weight caused by excessive thickness of the plate body and excessive occupation of internal space of the battery cell, thereby controlling costs and ensuring that the battery cell has a high energy density. And / or, by limiting the value of h1 to between 0.05 mm and 1 mm, it can be ensured that the first thermal insulation part has sufficient thermal insulation effect and realizes the thermal insulation function of the thermal insulation layer, and it can also avoid stress concentration of the coating due to the excessive thickness of the first thermal insulation part, and avoid the problem of cracks and peeling of the first thermal insulation part, thereby ensuring the reliability of the thermal insulation layer and further ensuring the thermal insulation effect.

[0011] In an optional embodiment, the outer peripheral side of the second thermal insulation part is suitable for being sleeved with a sealing ring, the lower surface of the sealing ring is in contact with the upper surface of the first thermal insulation part, the lower surface of the sealing ring is annular and has a ring width of W2, and the ring width of the first thermal insulation part is W1, wherein W1 is greater than W2.

[0012] Beneficial effect: By setting the lower surface of the sealing ring to fit with the upper surface of the first thermal insulation part, and the ring width W1 of the first thermal insulation part being larger than the ring width W2 of the annular shape of the lower surface of the sealing ring, direct contact between the sealing ring and the plate body is avoided, thereby effectively increasing the thermal insulation structure between the plate body 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.

[0013] In an optional embodiment, W1 and W2 satisfy the relationship: 0.2 mm ≤ W1 - W2 ≤ 0.6 mm; And / or, W1 and W2 satisfy the relationship: 0.8 mm ≤ W2 < W1 ≤ 3 mm.

[0014] Beneficial effect: By limiting the value of W1-W2 to between 0.2 mm and 0.6 mm, it can ensure that the first thermal insulation portion can provide sufficient thermal insulation width, prevent the sealing ring from aging due to heat, thereby improving the sealing performance and service life of the sealing ring, and avoid waste of materials and save costs; And / or, by limiting the value range to 0.8 mm≤W2<W1≤3 mm, it is possible to ensure that the sealing ring has sufficient sealing width, thereby ensuring the sealing performance, and to avoid the ring width of the first insulation part being too large and the sealing width of the sealing ring being too large, thereby avoiding waste of materials and saving costs.

[0015] In an optional embodiment, the column includes a rod and a head, the rod is connected between the plate and the head, and the second thermal insulation part is sleeved on the outer peripheral side of the rod; along the height direction, the total height of the thermal insulation layer is H1, the size of the rod is H2, and the size of the sealing ring after compression is H3, wherein the relationship between H1, H2, and H3 satisfies: H3+h1≤H1≤H2.

[0016] Beneficial effect: By limiting the relationship of H3+h1≤H1≤H2, it can be ensured that the insulation layer can provide sufficient insulation height for the sealing ring along the height direction, thereby ensuring that there is sufficient insulation area between the sealing ring and the pole body, effectively reducing the impact of welding heat on the sealing ring, avoiding material waste, and ensuring the flow capacity between the pole body and the riveted block.

[0017] In an optional embodiment, the value range of H1 is: 1.5 mm ≤ H1 ≤ 6 mm; And / or, the value range of H2 is: 2.5 mm≤H2≤6 mm.

[0018] Beneficial effect: 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; 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 assembly meets the use requirements, and to avoid the height of the pole body being too large and affecting the overall height of the cover assembly, thereby ensuring that the battery cell has a higher volume energy density.

[0019] In an optional embodiment, the thermal insulation layer is a coating structure.

[0020] Beneficial effects: The coating structure can be formed by directly coating on the surface of the pole body, without the need for additional assembly steps, easy to process, simple process, good adhesion to the surface of the pole body after forming, high fit, not easy to fall off, and can effectively block the transfer of heat.

[0021] In a second aspect, the present invention further provides a cover plate assembly comprising: a cover plate body having a pole hole defined therein; a rivet block disposed on one side of the cover plate body, the rivet block having a rivet hole defined therein corresponding to the pole hole; the aforementioned pole structure, wherein the plate body of the pole structure is located on a side of the cover plate body facing away from the rivet block, and a pole body is inserted into the pole hole and the rivet hole; and a sealing ring is fitted over the pole body. Because the cover plate assembly includes the pole structure and has the same effects as the pole structure, further description thereof will not be given here.

[0022] In a third aspect, the present invention further provides a battery cell comprising: a housing having an open end; an electrode group disposed within the housing; and the aforementioned cover plate assembly, the cover plate assembly being disposed over the open end of the housing. Because the battery cell includes the cover plate assembly, it has the same effects as the cover plate assembly and is not further described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 This is a structural diagram of the cover plate assembly and the electrode group welding before improvement; Figure 2 This is a schematic structural diagram of a pole structure according to an embodiment of the present invention; Figure 3 for Figure 2 A front view of the pole structure shown; Figure 4 for Figure 3 A partial enlarged schematic diagram of the middle A Figure 5 for Figure 2 A top view of the pole structure shown; Figure 6 Schematic diagram of the structure of the pole body according to an embodiment of the present invention; Figure 7 for Figure 6 A front view of the pole body is shown; Figure 8 A top view of a cover assembly according to an embodiment of the present invention Figure 9 for Figure 8 Cross-sectional view in CC direction; Figure 10 for Figure 9 A partial enlarged schematic diagram of B in the middle; Figure 11 for Figure 8 An exploded view of the cover assembly is shown; Figure 12 Schematic diagram of the structure of the sealing ring according to an embodiment of the present invention; Figure 13 for Figure 12 A cross-sectional view of the seal ring is shown.

[0025] Description of reference numerals: 1. Pole body; 110. Plate body; 111. First surface; 120. Column; 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 body; 401. Pole 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 group; 1001. Tab; 1002. Tab weld mark. DETAILED DESCRIPTION

[0026] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0027] Lithium-ion battery is a type of battery. As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields. The requirements for the performance and safety of lithium-ion batteries are increasing. The cover assembly is a key component in lithium-ion batteries. Its function is to weld with the shell to form a sealed cavity, lead the positive and negative electrodes of the electrode group, and serve as an assembly carrier. Figure 1 As shown, it is a schematic diagram of the positional relationship of the welding of the pole group 10 and the pole structure in the cover plate assembly before improvement. The pole ear 1001 is welded to the plate body 110 of the pole structure, and a pole ear weld mark 1002 is formed on the pole ear 1001 and the plate body 110. For the runway-type pole in the cover plate assembly, since the runway-type pole needs to withstand a large current, the welding of the plate body 110 and the pole ear 1001 must also be able to withstand a large current, which makes the welding melting area of ​​the pole ear 1001 and the plate body 110 larger, and the welding heat generation is larger. The high temperature generated by the welding will be transmitted along the pole to the sealing ring 3. The sealing ring 3 is affected by a large amount of welding heat and is easily deformed by heat or aged by heat, resulting in poor sealing or even failure, which in turn leads to unqualified sealing performance of the battery cell.

[0028] The following combination Figures 2 to 13 , describing embodiments of the present invention.

[0029] According to an embodiment of the present invention, on the one hand, a pole structure is provided, such as Figures 2 to 7 As shown, it includes: a pole body 1 and a heat-insulating layer 2. The pole body 1 includes a plate body 110 and a column 120. The column 120 is fixedly connected to the first side of the plate body 110 in the height direction. The surface of the first side of the plate body 110 is a first surface 111. The dimension of the plate body 110 in the height direction is h; the heat-insulating layer 2 includes a first heat-insulating portion 201 and a second heat-insulating portion 202. The first heat-insulating portion 201 is annular and surrounds the outer peripheral side of the column 120. The first heat-insulating portion 201 is attached to the first surface 111. The dimension of the first heat-insulating portion 201 in the height direction is h1. The second heat-insulating portion 202 is connected to the inner ring of the first heat-insulating portion 201 and is sleeved on the outer peripheral surface of the column 120. Wherein, the relationship between h and h1 satisfies the following equation: , k is the coefficient. The units of h and h1 are both mm.

[0030] 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 body 110 along the height direction, and the thickness of the first heat insulating portion 201 along the height direction. The inner ring of the first heat insulating portion 201 refers to the circumferential edge of the ring-shaped first heat insulating portion 201 close to the center thereof. The second heat insulating portion 202 is cylindrical. The plate body 110 has a first side and a second side arranged opposite to each other along the height direction. The first side of the plate body 110 is connected to the column 120, and the second side is used for welding with the pole ear 1001 of the pole group 10. The pole ear 1001 The welding heat generated when welding with the pole body 1 is transferred in the direction from the second side of the plate body 110 to the first side along the height direction, while the traditional sealing ring 3 is arranged on the first side of the plate body 110 and directly sleeved on the outer peripheral side of the column 120, which is easily affected by the welding heat; the relationship between h and h1 in this embodiment conforms to the law of heat transfer. It can be seen from the basic formula of thermal conductivity that under the same conditions, heat transfer is inversely proportional to distance. Therefore, the greater the thickness of the plate body 110, the less heat is transferred from the second side of the plate body 110 to the first side, and the smaller the thickness of the required first thermal insulation part 201.

[0031] By applying the pole structure of this embodiment, a thermal insulation layer 2 is added to the pole body 1, and the thermal insulation layer 2 includes a first thermal insulation portion 201 attached to the first surface 111 of the plate body 110, and a second thermal insulation portion 202 sleeved and attached to the column 120. The thermal insulation layer 2 can block the heat generated during the welding process of the pole body 1 and the pole ear 1001 from being transferred to other components arranged on the first side of the plate body 110, and by setting the thickness h1 of the first thermal insulation portion 201 to be inversely proportional to the thickness h of the plate body 110, which complies with the heat transfer law, the thickness of the first thermal insulation portion 201 can be reasonably set according to the thickness of the plate body 110, thereby effectively avoiding the influence of welding heat on the sealing ring 3, avoiding the sealing ring 3 from being deformed by heat or aged by heat and causing poor sealing, ensuring the sealing reliability of the sealing ring 3, and ensuring the qualified rate of the battery cell.

[0032] In one embodiment, the thermal insulation layer 2 is a coating structure. The coating structure can be formed by directly applying it to the surface of the pole body 1, without requiring additional assembly steps, facilitating processing and simplifying the process. After forming, the coating structure has good adhesion to the surface of the pole body 1, has a high degree of fit, is not easy to fall off, and can effectively block heat transfer.

[0033] Preferably, the thermal insulation layer 2 is a spray coating, which is easy to operate and convenient to form.

[0034] In one embodiment, the thermal insulation layer 2 is made of a ceramic coating such as aluminum oxide (Al2O3) or zirconium oxide (ZrO2). Such a coating has good low thermal conductivity and high temperature resistance.

[0035] In one embodiment, the value range of k is: 0.1≤k≤0.15. It should be noted that k is a coefficient and has no unit. The height dimension h1 of the first thermal insulation part 201 is inversely proportional to the height dimension h of the plate body 110. The thicker the plate body 110, the smaller the thickness of the first thermal insulation part 201. k is an inverse coefficient. If k is less than 0.1, the thickness of the first thermal insulation part 201 may be insufficient, resulting in poor thermal insulation effect. The heat generated by the welding of the pole body 1 and the tab 1001 may still be transferred to the sealing ring 3 in large quantities, causing the sealing ring 3 to deform due to heat or age due to heat, resulting in poor sealing. If k is greater than 0.15, the thickness of the first thermal insulation part 201 is too large, which wastes material. Moreover, when the first thermal insulation part 201 is a coating structure, the excessive thickness may cause the coating structure to crack and peel off, and the coating surface may be easily damaged, which will also damage the thermal insulation effect of the first thermal insulation part 201. In turn, the welding heat may be transferred to the sealing ring 3, causing the sealing ring 3 to melt and deform, affecting the sealing effect.

[0036] Therefore, by limiting the value of k to between 0.1 and 0.15, it is possible to ensure that the first thermal insulation part 201 has a sufficient thickness, thereby ensuring the thermal insulation effect of the first thermal insulation part 201, and avoid wasting materials due to the first thermal insulation part 201 being too thick, thereby saving costs. When the first thermal insulation part 201 is a coating structure, it is possible to avoid the first thermal insulation part 201 being too thick and causing the coating to crack and peel off, thereby ensuring the structural stability of the first thermal insulation part 201, and also ensuring its thermal insulation effect, thereby avoiding a large amount of heat generated during the welding of the tab 1001 and the plate body 110 from being transferred to the sealing ring 3, causing the sealing ring 3 to melt, deform, or age due to heat, thereby ensuring the sealing effect.

[0037] 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.

[0038] In one embodiment, the height dimension h of the plate 110 ranges from 0.8 mm to 3 mm. It should be noted that the terminal structure, as a critical component of the battery, needs to be able to withstand a certain degree of push-pull force without damage, loosening, or poor contact, to ensure the reliability of the battery's electrical connection and mechanical stability during use. If h < 0.8 mm, the thickness of the plate 110 is too small, the structural strength is insufficient, and the terminal body 1 is unable to withstand sufficient push-pull force. Furthermore, excessive heat is transferred from the second side of the plate 110 to the first side, significantly impacting the sealing ring 3. Accordingly, the thickness of the first thermal insulation portion 201 required is too large, which can easily cause the coating to crack and peel. If h > 3 mm, the plate 110 is too thick, resulting in excessive weight of the terminal body 1, increased cost, and excessive internal space occupied by the battery cell, affecting the overall energy density of the battery cell.

[0039] Therefore, by limiting the value of h to between 0.8 mm and 3 mm, it is possible to ensure that the plate body 110 has sufficient structural strength and that the pole body 1 can withstand the push-pull force required, thereby ensuring the reliability of the pole body 1, and avoid excessive heat transfer from the second side of the plate body 110 to the first side, thereby avoiding excessive thickness of the first thermal insulation part 201, avoiding excessive heat impact on the sealing ring 3, ensuring sealing performance, and avoiding excessive thickness of the plate body 110 resulting in excessive weight and excessive occupation of the internal space of the battery cell, thereby controlling costs and ensuring that the battery cell has a higher energy density.

[0040] 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 values.

[0041] In one embodiment, the dimension h1 of the first thermal insulation portion 201 along the height direction has a value range of: 0.05 mm ≤ h1 ≤ 1 mm. If h1 is less than 0.05 mm, the thermal insulation function is limited. If h1 is greater than 1 mm, the thickness of the first thermal insulation portion 201 is too large, and an overly thick coating may cause stress concentration, cracks, and even peeling. Therefore, by limiting h1 to a value between 0.05 mm and 1 mm, it is possible to ensure that the first thermal insulation portion 201 has a sufficient thermal insulation effect and realize the thermal insulation function of the thermal insulation layer 2, while avoiding stress concentration of the coating due to the excessive thickness of the first thermal insulation portion 201, and avoiding cracks and peeling problems in the first thermal insulation portion 201, thereby ensuring the reliability of the thermal insulation layer 2 and further ensuring the thermal insulation effect.

[0042] 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 values.

[0043] The following examples illustrate the effects of different values ​​of k on the performance of the pole structure. The test results of the embodiment and the comparative example are shown in Tables 1 to 3. The pole structure of the embodiment satisfies the relationship of 0.1≤k≤0.15; the pole structure of the comparative example does not satisfy the relationship of 0.1≤k≤0.15.

[0044] Case 1: The height dimension of the plate 110 is h = 1 mm. Different values ​​of coefficient k are taken to calculate different values ​​of h1 (the height dimension of the first heat insulating portion 201). The pole structures corresponding to different values ​​of h1 are used to assemble the 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 (the leakage rate is required to be ≤ 1×10 -7 Pa.m 3 / s), and the results are shown in Table 1.

[0045] Table 1

[0046] Case 2: The height dimension of the plate 110 is h = 1.5 mm. Different values ​​of coefficient k are used to calculate different values ​​of h1 (the height dimension of the first heat insulating portion 201). The pole structures corresponding to different h1 values ​​are assembled into 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 (the leakage rate is required to be ≤ 1×10 -7 Pa.m 3 / s), and the results are shown in Table 2.

[0047] Table 2

[0048] Case 3: The height dimension of the plate 110 is h = 1.8 mm. Different values ​​of coefficient k are used to calculate different values ​​of h1 (the height dimension of the first heat insulating portion 201). The pole structures corresponding to different values ​​of h1 are used to assemble the 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 (the leakage rate is required to be ≤ 1×10 -7 Pa.m 3 / s), and the results are shown in Table 3.

[0049] Table 3

[0050] It can be seen from Tables 1 to 3 that in Examples 1-1 to 1-5, Examples 2-1 to 2-5, and Examples 3-1 to 3-5, the values ​​of k are all within the range of 0.1 to 0.15 specified in this application, and the leakage rates of the cover plate assemblies are all less than or equal to 1×10 -7 Pa.m 3 / s, which meets the requirements; however, in Comparative Examples 1-1 to 1-3, Comparative Examples 2-1 to 2-3, and Comparative Examples 3-1 to 3-3, the values ​​of k are all less than 0.1, which are not within the scope defined in this application, and the leakage rates of the cover plate assemblies are all greater than 1×10 -7 Pa.m 3 / s, which does not meet the requirements; in Comparative Examples 1-4 to Comparative Examples 1-6, Comparative Examples 2-4 to Comparative Examples 2-6, and Comparative Examples 3-4 to Comparative Examples 3-6, the values ​​of k are all greater than 0.15, which are not within the range defined in this application, and the leakage rates of the cover plate assemblies are all greater than 1×10 -7 Pa.m 3 / s, does not meet the requirements.

[0051] In summary, when h and h1 satisfy the relationship: When k is within the range of 0.1 to 0.15, the cover assembly of the battery cell composed of this pole structure meets the leakage rate requirements, indicating that the sealing ring 3 has not failed due to heat melting, and the corresponding spraying thickness of the thermal insulation layer 2 is optimal.

[0052] In one embodiment, further combined Figure 9 and Figure 10 As shown, the outer peripheral side of the second heat insulating portion 202 is suitable for being sleeved with a sealing ring 3, and the lower surface of the sealing ring 3 is in contact with the upper surface of the first heat insulating portion 201. The lower surface of the sealing ring 3 is annular and has a ring width of W2. The ring width of the first heat insulating portion 201 is W1, wherein W1 is greater than W2. The lower surface of the sealing ring 3 refers to the surface of the side of the plate 110 that the sealing ring 3 faces in the height direction, that is, the lower surface refers to the side of the plate 110 that the sealing ring 3 faces in the height direction. Figure 10 The upper surface of the first heat insulating portion 201 refers to the surface of the first heat insulating portion 201 facing away from the plate 110 in the height direction, that is, the upper surface refers to the surface along the Figure 10 The surface in the "upward" direction indicated by the middle arrow. By arranging the lower surface of the sealing ring 3 to be in contact with the upper surface of the first thermal insulation portion 201, and the ring width W1 of the first thermal insulation portion 201 being larger than the ring width W2 of the annular lower surface of the sealing ring 3, direct contact between the sealing ring 3 and the plate body 110 is avoided, thereby effectively adding a thermal insulation structure between the plate body 110 and the sealing ring 3, reducing the influence of welding heat on the sealing ring 3, and improving the sealing performance and service life of the sealing ring 3.

[0053] 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 peripheral side 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 peripheral side of the rod portion 121. The first ring portion 301 is compressed between the cover body 4 and the plate body 110 to ensure sealing. Among them, the upper surface refers to Figure 10 and Figure 13 The arrow in the middle points to the surface in the "up" direction, and the lower surface refers to Figure 10 and Figure 13 The outer peripheral side of the second ring portion 302 refers to the side of the second ring portion 302 that is away from its axis in a direction perpendicular to its axis; the division of the first ring portion 301 and the second ring portion 302 is as follows Figure 13 As shown by the dotted line, it should be noted that the dotted 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.

[0054] It should be noted that the annular ring width W2 of the lower surface of the sealing ring 3 is equal to the sum of the ring widths of the first ring portion 301 and the second ring portion 302. The area on the sealing ring 3 located between the plate body 110 and the cover body 4 is the main sealing area. By setting this area to be located on the side of the first insulation portion 201 away from the plate body 110, and W1 being greater than W2, the first insulation portion 201 extends beyond the sealing ring 3 along the ring width direction, which can reduce the main sealing area of ​​the sealing ring 3 from being affected by high temperature, thereby improving the sealing performance.

[0055] 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 assembly, it is in a compressed state. The size 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 is larger than before compression. Among them, 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 assembled in the cover assembly and compressed.

[0056] In one embodiment, the relationship between W1 and W2 satisfies the following equation: 0.2 mm ≤ W1-W2 ≤ 0.6 mm. It should be noted that if W1-W2 is less than 0.2 mm, the width of the first thermal insulation portion 201 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 thermal insulation width provided by the first thermal insulation portion 201 is insufficient, resulting in thermal aging of the sealing ring 3 and affecting its service life; if W1-W2 is greater than 0.6 mm, the width of the first thermal insulation portion 201 beyond the sealing ring 3 is too large, and the ring width of the first thermal insulation portion 201 is too large, which increases the cost. Therefore, by limiting W1-W2 to a value between 0.2 mm and 0.6 mm, it can be ensured that the first thermal insulation portion 201 can provide sufficient thermal insulation width, avoid thermal aging of the sealing ring 3, thereby improving the sealing and service life of the sealing ring 3, and avoid waste of materials and save costs.

[0057] 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 reduced sealing performance. If W1 > 3 mm, the ring width of the first thermal insulation portion 201 is too large, wasting material, and the sealing area of ​​the sealing ring 3 is redundant, occupying the internal space of the cover plate and increasing costs. Therefore, by limiting the value range to 0.8 mm ≤ W2 < W1 ≤ 3 mm, it is possible to ensure that the sealing ring 3 has a sufficient sealing width, thereby ensuring sealing performance, while also preventing the ring width of the first thermal insulation portion 201 from being too large and the sealing width of the sealing ring 3 from being too large, thereby avoiding material waste and saving costs.

[0058] In one embodiment, further combined Figures 6 and 7As shown, the column 120 includes a rod 121 and a head 122. The rod 121 is connected between the plate 110 and the head 122, and further combined with Figures 2 to 4 and Figure 10 As shown, the second insulation part 202 is sleeved on the outer peripheral side of the rod part 121; along the height direction, the total height of the 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, wherein 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 as a whole between the first plastic part 6 and the first thermal insulation part 201, H3 is equal to the distance between the surface of the first plastic part 6 that abuts the upper surface of the second ring part 302 of the sealing ring 3 and the upper surface of the first thermal insulation part 201; H1 is equal to the dimension of the second thermal insulation part 202 of the thermal insulation layer 2 in the height direction, that is, the distance between the upper surface of the second thermal insulation part 202 and the first surface 111 of the plate body 110; H2 is equal to the distance between the lower surface of the rivet block 5 and the plate body 110; the distance between the lower surface of the sealing ring 3 and the first surface 111 of the plate body 110 is equal to h1.

[0059] It should be noted that the sealing ring 3 is located on the outer peripheral side of the rod 121, and the upper surface of the sealing ring 3 will not exceed the upper end surface of the rod 121, so the second thermal insulation part 202 does not need to exceed the rod 121 in the height direction, that is, H1 is less than or equal to H2. If H1 is greater than H2, it wastes materials, and the second thermal insulation part 202 extends between the head 122 and the riveted block 5, affecting the electrical conductivity between the head 122 and the riveted block 5, thereby affecting the current flow capacity between the pole body 1 and the riveted block 5; if H1<H3+h1, the size of the second thermal 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 thermal insulation part 201, so that the upper surface of the second thermal insulation part 202 is lower than the upper surface of the sealing ring 3. The thermal insulation area provided by the second thermal insulation part 202 is insufficient, and the heat from the welding of the plate body 110 and the pole ear 1001 is transferred to the sealing ring 3 through the rod 121, affecting the sealing performance and life of the sealing ring 3. Among them, the upper surface refers to Figure 10 The arrow in the middle points to the surface in the "up" direction, and the lower surface refers to Figure 10 The surface in the direction of "down" indicated by the middle arrow.

[0060] Therefore, by defining the relationship H3+h1≤H1≤H2, it can be ensured that the insulation layer 2 can provide sufficient insulation height for the sealing ring 3 along the height direction, thereby ensuring that there is sufficient insulation area between the sealing ring 3 and the pole body, effectively reducing the impact of welding heat on the sealing ring 3, avoiding material waste, and ensuring the flow capacity between the pole body 1 and the riveted block.

[0061] It should be noted that by positioning the first insulation portion 201 of the insulation layer 2 between the first surface 111 of the plate 110 and the lower surface of the sealing ring 3, and the second insulation portion 202 between the outer circumference of the rod 121 and the inner circumference of the sealing ring 3, an insulation layer is added to the mating surface between the pole body 1 and the sealing ring 3, thereby effectively achieving a thermal insulation effect between the pole body 1 and the sealing ring 3. The head 122 of the pole 120 is inserted into the rivet hole 501 in the rivet block 5 and is riveted to the rivet block 5, while the rod 121 is supported between the rivet block 5 and the plate 110.

[0062] In one embodiment, the value range of H1 is: 1.5 mm ≤ H1 ≤ 6 mm. If H1 is less than 1.5 mm, the size of the second thermal insulation part 202 in the height direction is too small, and it cannot be ensured that the upper surface of the second thermal insulation part 202 is higher than the upper surface of the sealing ring 3, which easily leads to direct contact between the sealing ring 3 and the column 120 and the contact surface is too large. The second ring portion 302 of the sealing ring 3 is greatly affected by heat, and it ages or even melts, affecting the sealing effect of the sealing ring 3; if H1 is greater than 6 mm, the size of the second thermal insulation part 202 in the height direction is too large, exceeding the range of the sealing ring 3, and wasting materials. Therefore, by limiting H1 to a value between 1 mm and 6 mm, it can be ensured that the second thermal insulation part 202 can provide a sufficient insulation height, thereby ensuring the thermal insulation effect of the thermal insulation layer 2, effectively reducing the impact of welding heat on the sealing ring 3, ensuring sealing performance, and avoiding waste of materials and saving costs.

[0063] In one embodiment, the value range of H2 is: 2.5 mm ≤ H2 ≤ 6 mm. If H2 is less than 2.5 mm, the height of the rod 121 is too small, the structural strength is insufficient, and the strength of the cover assembly does not meet the use requirements; if H2 is greater than 6 mm, the height of the rod 121 is too large, resulting in the overall size of the cover assembly being too large in the height direction, the overall volume of the cover assembly being too large, not meeting the requirements, and the volume capacity of the battery cell being insufficient. 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 pole body 1 and the cover assembly meets the use requirements, and to avoid the height of the pole body 1 being too large and affecting the overall height of the cover assembly, thereby ensuring that the battery cell has a high volume energy density.

[0064] According to an embodiment of the present invention, on the other hand, a cover plate assembly is provided. Figures 8 to 13As shown, the cover plate assembly includes: a cover plate body 4, a rivet block 5, the aforementioned pole structure, and a sealing ring 3. The cover plate body 4 defines a pole hole 401; the rivet block 5 is disposed on one side of the cover plate body 4 and defines a rivet 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 facing away from the rivet block 5, with the pole 120 inserted through the pole hole 401 and the rivet hole 501. The sealing ring 3 is sleeved onto the pole 120. Specifically, the sealing ring 3 sleeves onto the outer periphery of the stem 121 of the pole 120 and is located between the thermal insulation layer 2 on the pole body 1 and the cover plate body 4.

[0065] In the cover plate assembly of this embodiment, the pole structure adds a thermal insulation coating to a local area of ​​the surface of the pole body 1 (and the mating surface of the sealing ring 3), which can improve the influence of the high temperature generated when the pole ear 1001 and the pole structure are welded on the sealing ring 3, and can effectively avoid abnormal sealing performance caused by the melting deformation or aging of the sealing ring 3 due to heat, thereby ensuring the sealing performance of the sealing ring 3 and improving the qualified rate of the battery cell.

[0066] In one embodiment, the cover assembly further includes: a first plastic part 6 and a second plastic part 7. The first plastic part 6 is arranged between the rivet block 5 and the cover body 4 to ensure insulation between the rivet block 5 and the cover body 4. A first through hole 601 corresponding to the pole hole 401 is provided on the first plastic part 6, and a partial section of the rod 121 of the column 120 close to the head 122 is passed through the first through hole 601; the second plastic part 7 is arranged on a side of the cover body 4 away from the first plastic part 6. A second through hole 701 is provided on the second plastic part 7. A partial section of the rod 121 of the column 120 close to the plate body 110 is passed through the second through hole 701. The plate body 110 is located on the side of the second plastic part 7 away from the cover body 4. The plate body 110 presses the second plastic part 7 toward the cover body 4. The second plastic part 7 is used to ensure insulation between the cover body 4 and the pole group.

[0067] In one embodiment, the first plastic part 6 is an upper plastic and the second plastic part 7 is a lower plastic.

[0068] In one embodiment, the cover assembly further includes an explosion-proof valve 8. An explosion-proof valve hole is further provided on the cover body 4. The explosion-proof valve 8 is disposed in the explosion-proof valve hole. The explosion-proof valve 8 is adapted to open when the air pressure inside the battery reaches a preset value, thereby discharging high-temperature flue gas in the battery in a timely manner to prevent the battery from exploding. An explosion-proof patch 9 is affixed to the explosion-proof valve 8 to protect the explosion-proof valve.

[0069] According to another aspect of an embodiment of the present invention, a battery cell is provided, comprising: a housing, an electrode group, and the aforementioned cover plate assembly. The housing has an open end; the electrode group is disposed within the housing; and the cover plate 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.

[0070] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

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

2. The pole structure according to claim 1, characterized in that: The outer peripheral side of the second thermal insulation part is suitable for being sleeved with a sealing ring, the lower surface of the sealing ring is in contact with the upper surface of the first thermal insulation part, the lower surface of the sealing ring is annular and has a ring width of W2, and the ring width of the first thermal insulation part is W1, wherein W1 is greater than W2.

3. The pole 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 relationship: 0.8 mm ≤ W2 < W1 ≤ 3 mm.

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

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

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

7. A cover plate assembly, characterized in that: include: The cover body is provided with a pole hole; A rivet block is provided on one side of the cover body, and a rivet hole corresponding to the pole hole is opened on the rivet block; The pole structure according to any one of claims 1 to 6, wherein the plate body of the pole structure is located on a side of the cover body away from the rivet block, and the column body is inserted into the pole hole and the rivet hole; The sealing ring is sleeved on the column.

8. A battery cell, characterized in that: include: a housing having an open end; a pole group, disposed in the housing; The cover plate assembly according to claim 7 is provided on the open end of the shell.

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