Connecting piece and rubber coating matching structure, battery cell and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a connecting piece and rubber coating matching structure, a battery cell and a battery pack. The connecting piece and rubber coating matching structure comprises a connecting piece, the connecting piece comprises a pole connecting area, a fusing area and a tab connecting area which are sequentially connected in the first direction, the fusing area comprises a fusing part and a through hole, the size of the through hole in the first direction is X, the total area of projections of the fusing part on the cross section which passes through the center of the through hole and is perpendicular to the first direction is S, and a # imgabs0 # rubber coating layer is arranged between the connecting piece and the tab connecting area. The connecting piece is provided with a wrapping part and a filling part, the wrapping part wraps the surface of the fusing part and extends out of the fusing area in the first direction, the filling part is connected with the wrapping part and fills the through hole, the size of the part, located on the lower side of the connecting piece, of the wrapping part in the vertical direction is c, and c is larger than or equal to 0.3 mm and smaller than or equal to 3 mm. Therefore, the circuit can be completely cut off when the connecting sheet is fused, and the molten liquid of the connecting sheet is prevented from dropping on the pole group to cause thermal runaway, so that the safety is improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a connecting piece and rubber encapsulation matching structure, a battery cell and a battery pack. Background Art

[0002] The connector is a crucial component in a battery cell, connecting the tabs of the electrode group to the posts on the cover plate, achieving electrical connection between the electrode group and the cover plate assembly. To improve battery cell safety, a fuse is typically installed on the connector. In the event of a short circuit, the fuse quickly blows, disconnecting the connector and the electrode group from the posts, preventing further violent reactions in the cell.

[0003] However, when the fuse is triggered and blows, the connecting piece breaks into two halves. If the two halves are too close to each other after the break, arcing may continue between them, causing the pole group and the pole to reconnect, thus failing to completely cut off the circuit, which is very dangerous. Alternatively, when the fuse of the connecting piece melts, the melted liquid drips onto the pole group, which will continue to trigger thermal runaway, which is also more dangerous. Summary of the Invention

[0004] In view of this, the present invention provides a connecting piece and rubber coating matching structure, a battery cell and a battery pack to solve the problem that the circuit cannot be completely cut off when the connecting piece melts or the melted liquid of the connecting piece drips onto the electrode group and causes thermal runaway.

[0005] In a first aspect, the present invention provides a connecting piece and rubber encapsulation matching structure, comprising: a connecting piece, comprising a pole connection area, a fuse area, and a tab connection area sequentially connected along a first direction, the fuse area comprising a fuse portion and a through hole, the through hole having a dimension X along the first direction, the total projected area of the fuse portion on a cross section passing through the center of the through hole and perpendicular to the first direction being S, wherein: The rubber layer has a covering portion and a filling portion, wherein the covering portion covers the surface of the fuse portion and extends beyond the fuse zone along a first direction, the filling portion is connected to the covering portion and fills the through hole, and the size of the portion of the covering portion located on the lower side of the connecting piece along the up and down direction is c, wherein 0.3mm≤c≤3mm.

[0006] Beneficial effect: by setting the covering portion of the rubber layer to cover the surface of the fuse part and extend to outside the fuse area along the first direction, and the filling portion to fill the through hole, that is, the rubber layer can wrap the entire fuse area, then when the connecting piece is melted from the fuse area, the rubber layer can play an insulating and isolating role at the fracture, and because the covering portion extends to outside the fuse area along the first direction, that is, the rubber layer can overlap the connecting piece body on both sides of the through hole along the first direction, when the fuse part is melted, the plastic originally located on the surface of the fuse part is heated and melted, causing the filling part to lose its overlapping support and fall into the battery cell. In addition, by limiting X to 0.5mm to Taking the value within the range can not only avoid the arc short circuit phenomenon between the two half-piece connecting pieces under high voltage after the fuse part blows, and ensure that the circuit can be completely cut off when the connecting piece blows, but also ensure the structural strength of the connecting piece during normal working state, thereby improving the reliability of the connecting piece and ensuring the safety of the battery cell. At the same time, by setting the dimension c of the part of the covering portion located on the lower side of the connecting piece in the up and down directions to take a value within the range of 0.3mm to 3mm, it is ensured that the part of the covering portion located on the lower side of the connecting piece has a certain thickness, which can ensure that the part will not be melted when the fuse part blows, thereby preventing the melted liquid of the connecting piece from dripping onto the electrode group and causing thermal runaway, thereby improving safety, saving costs, and improving the space utilization rate inside the battery cell.

[0007] In an optional embodiment, the covering portion covers the surface of the fuse portion and extends along a first direction toward both sides of the fuse zone, and a dimension of the covering portion along the first direction is b, wherein 1.2≤b / X≤5.

[0008] Beneficial effects: It can ensure that the part of the covering part overlapping the connecting piece body outside the through hole can provide sufficient support for the filling part, preventing the filling part from falling into the battery cell, thereby ensuring the insulating and separating effect of the rubber layer, ensuring that the circuit can be completely cut off when the connecting piece melts, improving safety, avoiding waste of materials, thereby saving costs, and also helping to improve the energy density of the battery cell.

[0009] In an optional embodiment, the total projected area S of the fuse portion on a cross section passing through the center of the through hole and perpendicular to the first direction is in the range of: 4 mm 2 ≤S≤12mm 2 .

[0010] Beneficial effects: It can ensure that the connecting piece has sufficient strength and the stability of the connecting piece structure, and can also ensure that the fuse part can be melted in time when the battery cell is short-circuited, thereby ensuring the safety of the battery cell.

[0011] In an optional embodiment, a dimension of the fuse portion in the vertical direction is t, and a dimension of a portion of the covering portion located on the upper side of the connecting piece in the vertical direction is a, wherein 0.5≤a / t≤5.

[0012] Beneficial effects: It can ensure that when the fuse part blows, the melted plastic on the covering part on the upper side of the connecting piece can fill the barrier area formed after the fuse part blows, play an insulating barrier role, avoid continuous short circuit caused by high-voltage arcing, thereby ensuring the safety of the battery cell, saving costs, and helping to improve the space utilization inside the battery cell.

[0013] In an optional embodiment, the dimension t of the fuse portion along the up and down directions has a value range of: 0.6 mm ≤ t ≤ 2 mm.

[0014] Beneficial effects: It can ensure that the connecting piece has sufficient structural strength and improve the reliability of the connecting piece, and it can also control the production cost and increase the volume energy density of the battery cell.

[0015] In an optional embodiment, the covering portion protrudes beyond the melting zone along a second direction, and the distance d by which the covering portion extends beyond the melting zone in the second direction has a value range of: 0.3 mm ≤ d ≤ 3 mm, wherein the second direction is perpendicular to the first direction in the plane where the upper surface of the connecting piece is located.

[0016] Beneficial effect: It can ensure that when the fuse part blows, the melted plastic on the covering part on the upper side of the connecting piece can fill the barrier area formed after the fuse part blows, play an insulating barrier role, avoid continuous short circuit caused by high-voltage arcing, thereby ensuring the safety of the battery cell, and can control costs and avoid waste of materials.

[0017] In an optional embodiment, along the second direction, the minimum distance from the edge of the through hole to the side of the connecting piece is e, where 1.5 mm ≤ e ≤ 20 mm.

[0018] Beneficial effect: It can ensure that the connecting piece has sufficient structural strength, avoid the connecting piece from bending and deforming under mechanical impact, and improve the reliability of the connecting piece; it can also ensure that the fuse part can be melted in time when the battery cell is short-circuited, thereby improving the safety of the battery cell.

[0019] In an optional embodiment, two sides of the through hole along the second direction are configured as rounded corners, and the radius of the circle where the rounded corners are located is R, where R=X / 2.

[0020] Beneficial effects: By constructing the two sides of the through hole along the second direction into rounded corners and the radius R of the circle where the rounded corners are located is half of the dimension X of the through hole along the first direction, the through hole is oblong, the outer contour of the through hole has a smooth transition, the structural strength is good and it is easy to process, the connecting piece is not easy to break under mechanical impact, the reliability is high, and the safety is good.

[0021] In the second aspect, the present invention also provides a battery cell, comprising: a shell having an open end; a pole group arranged in the shell, the pole group having a pole lug; a cover plate arranged at the open end of the shell to close the shell, the cover plate being provided with a pole; the above-mentioned connecting piece and the rubber encapsulation matching structure, the pole connection area of the connecting piece is connected to the pole and the pole lug connection area is connected to the pole lug.

[0022] Because the battery cell includes a connecting piece and a rubber encapsulating matching structure, it has the same effect as the connecting piece and the rubber encapsulating matching structure, and will not be described in detail here.

[0023] In a third aspect, the present invention further provides a battery pack comprising the above-mentioned battery cell. Since the battery pack comprises the battery cell and has the same effects as the battery cell, no further details will be given here. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] 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.

[0025] Figure 1 A top view of a connecting piece and rubber encapsulation matching structure according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 A cross-sectional view of the structure of the connecting piece and the rubber encapsulation in the MM direction is shown;

[0027] Figure 3 for Figure 2 A partial enlarged schematic diagram of F in the middle;

[0028] Figure 4 A top view of a connecting piece according to an embodiment of the present invention;

[0029] Figure 5 for Figure 4 A cross-sectional view of the connecting piece shown in the NN direction;

[0030] Figure 6 for Figure 4 A front view of the connecting piece shown;

[0031] Figure 7 A top view of another connecting piece according to an embodiment of the present invention;

[0032] Figure 8 This is a cross-sectional view of the connecting piece and the rubber coating matching structure according to an embodiment of the present invention after the fuse portion is blown and the upper side of the rubber coating is melted and deformed.

[0033] Description of reference numerals:

[0034] 1. Connecting piece; 110. Pole connection area; 120. Fusing area; 121. Fusing part; 122. Through hole; 130. Tab connection area; 2. Rubber coating; 210. Covering part; 220. Filling part. DETAILED DESCRIPTION

[0035] 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.

[0036] The following combination Figures 1 to 8 , describing embodiments of the present invention.

[0037] According to an embodiment of the present invention, on the one hand, a connecting piece and rubber coating matching structure is provided, comprising: a connecting piece 1 and a rubber coating layer 2. The connecting piece 1 comprises a pole connection area 110, a fuse area 120, and a tab connection area 130 sequentially connected along a first direction. The fuse area 120 comprises a fuse portion 121 and a through hole 122. The dimension of the through hole 122 along the first direction is X. The total projected area of the fuse portion 121 on a cross section passing through the center of the through hole 122 and perpendicular to the first direction is S, wherein: The rubber layer 2 has a covering portion 210 and a filling portion 220. The covering portion 210 covers the surface of the fuse portion 121 and extends along the first direction to the outside of the fuse zone 120. The filling portion 220 is connected to the covering portion 210 and fills the through hole 122. The size of the covering portion 210 located on the lower side of the connecting piece 1 along the vertical direction is c, where 0.3mm≤c≤3mm. The first direction refers to Figures 1 to 4 and Figure 7 The middle arrow points to the "first direction"; the up and down directions refer to Figures 2 to 3 The arrow in the middle points to the direction of "up and down".

[0038] The connecting piece and the rubber coating matching structure of the present embodiment are applied, and the covering portion 210 of the rubber coating layer 2 is provided to cover the surface of the fuse part 121 and extend to the outside of the fuse area 120 along the first direction, and the filling portion 220 is filled in the through hole 122, that is, the rubber coating layer 2 can completely wrap the fuse area 120. Then, when the connecting piece 1 is melted from the fuse area 120, the rubber coating layer 2 can play an insulating and isolating role at the fracture. Moreover, since the covering portion 210 extends to the outside of the fuse area 120 along the first direction, that is, the rubber coating layer 2 can overlap the connecting piece body on both sides of the through hole 122 along the first direction, when the fuse part 121 is melted, the filling portion 220 loses its overlapping support and falls into the interior of the battery cell due to the heat melting of the plastic originally located on the surface of the fuse part 121. In addition, by limiting X to 0.5mm to Taking the value within the range can not only avoid the arc short circuit phenomenon between the two half-piece connecting pieces under high voltage after the fuse part 121 melts, and ensure that the circuit can be completely cut off when the connecting piece 1 melts, but also ensure the structural strength of the connecting piece 1 during normal working state, thereby improving the reliability of the connecting piece 1 and ensuring the safety of the battery cell. At the same time, by setting the dimension c of the part of the covering portion 210 located on the lower side of the connecting piece 1 in the up and down directions to take a value in the range of 0.3mm to 3mm, it is ensured that the part of the covering portion 210 located on the lower side of the connecting piece 1 has a certain thickness, which can ensure that the part will not be melted when the fuse part 121 melts, thereby preventing the melted liquid of the connecting piece 1 from dripping onto the electrode group and causing thermal runaway, thereby improving safety, saving costs, and improving the space utilization rate inside the battery cell.

[0039] It should be noted that the connecting piece 1 is made of metal, and the fuse part 121 and the through hole 122 in the melting zone 120 are arranged along the second direction, wherein the second direction is the direction perpendicular to the first direction in the plane where the upper surface of the connecting piece 1 is located. Since the through hole 122 is provided on the melting zone 120, the solid part on the melting zone 120 is reduced (i.e., the melting part 121 is formed), the cross-sectional area is reduced, and the resistance is increased. When current flows through, the heat generated on the melting part 121 is large. Therefore, when the battery short-circuits and generates a transient large current, the melting part 121 melts due to the excessive heat, causing the connecting piece 1 to break from the melting zone 120, thereby cutting off the circuit and achieving the function of protecting the battery. Among them, the upper surface refers to Figure 2 The surface in the "up" direction indicated by the arrow in the middle.

[0040] It should be noted that the cross section of the center of the through hole 122 perpendicular to the first direction refers to Figure 4 The NN section in FIG. 1 shows the total cross-sectional area of the fuse portion 121 ( Figure 5The shaded area (in the middle) is the total projected area S of the fuse portion 121 on a cross section perpendicular to the first direction through the center of the through-hole 122. The dimension X of the through-hole 122 along the first direction is equal to the dimension X of the fuse portion 121 along the first direction. When a battery short circuit causes the fuse portion 121 of the connecting piece 1 to melt, the distance between the two broken connecting pieces is X. If X is less than 0.5 mm, X is too small. Even after the fuse portion 121 melts, an arc short circuit may still occur between the two connecting pieces under high voltage, posing a high risk. If X is greater than half of S, X is too large, resulting in a weak structural strength of the connecting piece 1 and a tendency to break under mechanical impact, which also affects the safety of the battery cell.

[0041] In addition, the rubber layer 2 is made of plastic. The portion of the covering portion 210 located on the lower side of the connecting piece 1 can receive the molten metal when the fuse 121 melts, preventing the melted metal from dripping onto the electrode group and further aggravating thermal runaway. Therefore, it is necessary to ensure that the portion of the covering portion 210 located on the lower side of the connecting piece 1 has a certain thickness so as not to melt when heated. If the dimension c of the portion of the covering portion 210 located on the lower side of the connecting piece 1 in the vertical direction is less than 0.3 mm, the thickness of the portion of the covering portion 210 located on the lower side of the connecting piece 1 If the size is too small, the heat generated on the fuse 121 when the battery cell is short-circuited will melt the portion of the covering 210 located on the lower side of the connecting piece 1, causing the metal and plastic to melt and drip onto the electrode group, further aggravating thermal runaway; if the dimension c of the portion of the covering 210 located on the lower side of the connecting piece 1 along the vertical direction is greater than 3mm, then the thickness of the portion of the covering 210 located on the lower side of the connecting piece 1 is too large, the weight is too large, the cost is high, and it will occupy too much space in the vertical direction, which is not conducive to improving the utilization rate of the internal space of the battery cell. It should be noted that the high temperature generated on the fuse 121 when the battery cell is short-circuited is instantaneous. After the fuse 121 is melted, no high temperature is generated. It is sufficient to ensure that the portion of the covering 210 located on the lower side of the connecting piece 1 is not melted at the instantaneous high temperature.

[0042] The matching structure of the connecting piece and the rubber coating in this embodiment simultaneously limits the value range of the dimension X of the through hole 122 along the first direction and the dimension c of the portion of the covering portion 210 located on the lower side of the connecting piece 1 along the vertical direction. This not only solves the problem of the circuit not being completely cut off when the connecting piece melts, but also solves the problem of thermal runaway caused by the melted liquid of the connecting piece dripping onto the electrode group.

[0043] In one embodiment, the covering portion 210 covers the surface of the fuse 121 and extends along a first direction toward both sides of the fuse region 120. The dimension of the covering portion 210 along the first direction is b, where 1.2 ≤ b / X ≤ 5. In the first direction, a portion of the covering portion 210 overlaps the connecting piece body on both sides of the through hole 122 of the connecting piece 1. This helps improve the stability of the covering portion 210's overlap with the connecting piece 1 after the fuse 121 has blown, thereby further preventing the filling portion 220 from falling into the battery cell. Both b and X are expressed in mm.

[0044] The dimension b of the covering portion 210 along the first direction is greater than the dimension X of the through hole 122 along the first direction. The larger the ratio of the dimension b of the covering portion 210 along the first direction to the dimension X of the through hole 122 along the first direction, the more the covering portion 210 overlaps with the portion outside the through hole 122, and the better the supporting effect of the rubber coating layer 2 on the filling portion 220. If b / X is less than 1.2, the portion of the covering portion 210 overlapping the connecting piece body outside the through hole 122 is too small, and the supporting effect on the filling portion 220 is insufficient. When the rubber coating corresponding to the fuse part 121 is heated and melted, there is still a risk that the filling part 220 falls into the interior of the battery cell, which causes the rubber coating layer 2 to fail to play an insulating and isolating role at the through hole 122. High-voltage arcing is easily generated at the through hole 122, that is, the circuit cannot be completely cut off, and there is a continuous short circuit phenomenon; if b / X is greater than 5, the covering part 210 overlaps too much on the connecting piece body outside the through hole 122, which wastes materials, increases costs, and increases weight, which is not conducive to improving the energy density of the battery cell. Therefore, by limiting the dimension b of the covering portion 210 along the first direction and the dimension X of the through hole 122 along the first direction to satisfy the ratio relationship of 1.2≤b / X≤5, it can be ensured that the portion of the covering portion 210 overlapping the connecting piece body outside the through hole 122 can provide sufficient support for the filling portion 220, thereby preventing the filling portion 220 from falling into the battery cell, thereby ensuring the insulating and isolating function of the rubber layer 2, and ensuring that the circuit can be completely cut off when the connecting piece 1 melts, thereby improving safety, avoiding waste of materials, thereby saving costs, and also helping to improve the energy density of the battery cell.

[0045] Preferably, the two portions of the covering portion 210 extending out of both sides of the melting zone 120 along the first direction have equal sizes in the first direction, further improving the stability of the overlapping of the covering portion 210 on the connecting piece body outside the through hole 122 .

[0046] In one embodiment, the dimension X of the through hole 122 along the first direction is in the range of 0.5 mm ≤ X ≤ 6 mm. It should be noted that if X is greater than 6 mm, the connecting piece 1 is too large, the structural strength is poor, and it is prone to breakage under mechanical impact, which also affects the safety of the battery cell. Therefore, by setting X to a value within the range of 0.5 mm to 6 mm, the arcing short circuit between the two connecting piece halves under high voltage after the fuse 121 blows can be avoided, while also ensuring the structural strength of the connecting piece 1 during normal operation, thereby improving the reliability of the connecting piece 1 and ensuring the safety of the battery cell.

[0047] In one embodiment, the total projected area S of the fuse portion 121 on the cross section perpendicular to the first direction at the center of the through hole 122 is in the range of: 4 mm 2 ≤S≤12mm 2 It should be noted that the larger the total projected area S of the fuse portion 121 on the cross section perpendicular to the first direction at the center of the through hole 122 is, the less likely it is to be fused. If S is greater than 12 mm 2 If S is too large, the fuse part 121 is difficult to melt when the battery cell is short-circuited, and the fuse area 120 cannot play the role of short-circuit protection. A large current continues to pass through the battery cell, and the battery cell is prone to dangerous situations such as combustion and explosion; if S is less than 4mm 2 , the cross-sectional area of the fuse part 121 is too small, the structural strength of the fuse area 120 is insufficient, and the stability of the connecting piece 1 is poor. Therefore, by setting the total projection area S of the fuse part 121 on the cross section perpendicular to the first direction at the center of the through hole 122 to 4mm 2 Up to 12mm 2 Taking the value within the range can not only ensure that the connecting piece 1 has sufficient strength and the stability of the structure of the connecting piece 1, but also ensure that the fuse part 121 can be melted in time when the battery cell is short-circuited, thereby ensuring the safety of the battery cell.

[0048] Specifically, for cells with a capacity lower than 90 Ah, the cross-sectional area S of the fuse 121 is 4 mm. 2 Correspondingly, the dimension X of the through hole 122 along the first direction is ≤ 2 mm; for a battery cell with a capacity of 90 Ah-130 Ah, the total cross-sectional area S of the fuse portion 121 is 6 mm 2 Correspondingly, the dimension X of the through hole 122 along the first direction is ≤3mm; for a battery cell with a capacity of 130Ah-160Ah, the total cross-sectional area S of the fuse portion 121 is 8mm 2 Correspondingly, the dimension X of the through hole 122 along the first direction is ≤ 4 mm, or the total cross-sectional area S of the fuse portion 121 is 10 mm 2 Correspondingly, the dimension X of the through hole 122 along the first direction is ≤5mm; for a battery cell with a capacity higher than 160Ah, the total cross-sectional area S of the fuse portion 121 is 12mm2 Correspondingly, the dimension X of the through hole 122 along the first direction is ≤6 mm.

[0049] In one embodiment, the size of the fuse part 121 in the vertical direction is t, and the size of the portion of the covering part 210 located on the upper side of the connecting piece 1 in the vertical direction is a, wherein 0.5≤a / t≤5. Figure 2 、 Figure 3 and Figure 5 The direction of "up and down" indicated by the middle arrow is the thickness of the fuse part 121, and the dimension of the part of the covering part 210 located on the upper side of the connecting piece 1 along the up and down direction is the thickness of the part; the upper side refers to Figures 2 to 3 The side of the "upper" direction indicated by the middle arrow, specifically, when the connecting piece 1 is installed in the battery cell, the upper side of the connecting piece 1 faces the cover plate, and the lower side of the connecting piece 1 faces the electrode group; when the battery cell is short-circuited, the fuse part 121 generates instantaneous high temperature. At the same time as the fuse part 121 melts, the plastic part of the rubber layer 2 close to the fuse part 121 is heated and melted. Under the action of gravity, the melted plastic collapses downward and fills the barrier area formed after the fuse part 121 melts, thereby playing an insulating barrier role. Figure 8 The figure shows a cross-sectional view of the structure of the connecting piece and the encapsulation after the fuse part 121 is melted. The cross-section is parallel to the MM cross-section and passes through the fuse part 121. The encapsulation part 210 is melted and filled into the barrier area between the connecting pieces of the two half pieces, thereby forming a structure in which the upper surface of the encapsulation part 210 is concave downward.

[0050] It should be noted that if a / t is less than 0.5, the thickness of the portion of the covering portion 210 located on the upper side of the connecting piece 1 is too small relative to the thickness of the connecting piece 1, and the melted plastic cannot fill the barrier area formed after the fuse portion 121 is melted. The barrier area cannot be formed, the insulation effect is poor, and there is still a high-voltage arc phenomenon between the two half-pieces of the connecting piece. The battery cell continues to short-circuit, which is very dangerous; if a / t is greater than 5, the thickness of the portion of the covering portion 210 located on the upper side of the connecting piece 1 is too large relative to the thickness of the connecting piece 1, the weight is too large, the cost is high, and it will occupy too much space in the upper and lower directions, which is not conducive to improving the utilization rate of the internal space of the battery cell. Therefore, by setting the relationship between the vertical dimension a of the portion of the covering portion 210 located above the connecting piece 1 and the vertical dimension t of the fuse portion 121 to satisfy 0.5≤a / t≤5, it is ensured that when the fuse portion 121 blows, the melted plastic of the covering portion 210 located above the connecting piece 1 will fully fill the barrier area formed by the melting of the fuse portion 121, thereby providing an insulating barrier and preventing a sustained short circuit caused by high-voltage arcing, thereby ensuring the safety of the battery cell, saving costs, and improving the space utilization within the battery cell. Wherein, a and t are both in mm.

[0051] In one embodiment, the dimension t of the fuse part 121 along the vertical direction has a value range of: 0.6mm≤t≤2mm. If the dimension t of the fuse part 121 along the vertical direction is less than 0.6mm, the thickness of the fuse part 121 is too small, the structural strength is poor, the connecting piece 1 is easily bent and deformed under mechanical impact, and the reliability is poor; if t is greater than 2mm, the thickness of the fuse part 121 is too large, the cost of the connecting piece 1 increases, and it is not conducive to improving the volume energy density of the battery cell. Therefore, by setting the dimension t of the fuse part 121 along the vertical direction to a value within the range of 0.6mm to 2mm, it is possible to ensure that the connecting piece 1 has sufficient structural strength and improve the reliability of the connecting piece 1, while also controlling production costs and improving the volume energy density of the battery cell.

[0052] In one embodiment, the covering portion 210 protrudes from the melting zone 120 along the second direction, and the distance d of the covering portion 210 beyond the melting zone 120 in the second direction is in the range of 0.3 mm ≤ d ≤ 3 mm, wherein the second direction refers to Figure 1 The "second direction" indicated by the middle arrow is perpendicular to the first direction within the plane of the upper surface of the connecting piece 1. It should be noted that when the fuse 121 blows, the covering 210 melts and fills the barrier zone formed by the fuse 121. If d is less than 0.3 mm, the covering 210 will be too small to fill the barrier zone formed by the fuse 121, and an effective barrier zone cannot be formed, resulting in poor insulation. If d is greater than 3 mm, the covering 210 will be too large to fill the barrier zone 120, resulting in excessive use of the rubber layer 2, waste of material, and high cost. Therefore, by setting the covering portion 210 to protrude from the melting zone 120 along the second direction, the covering portion 210 also protects the side edges of the melting zone 120 on both sides along the second direction, and by setting the distance d that the covering portion 210 is greater than the melting zone 120 in the second direction to be in the range of 0.3mm to 3mm, it can be ensured that when the melting portion 121 is blown, the melted plastic of the covering portion 210 located on the upper side of the connecting piece 1 can fill the barrier area formed after the melting of the melting portion 121, thereby playing an insulating barrier role, avoiding continuous short circuit caused by high-voltage arcing, thereby ensuring the safety of the battery cell, and controlling costs and avoiding waste of materials.

[0053] In one embodiment, along the second direction, the minimum distance between the edge of the through hole 122 and the side of the connecting piece 1 is e, where 1.5 mm ≤ e ≤ 20 mm. It should be noted that, along the second direction, the minimum distance e between the edge of the through hole 122 and the side of the connecting piece 1 is the minimum size of the fuse portion 121 along the second direction. If e is less than 1.5 mm, the distance between the through hole 122 and the side of the connecting piece 1 is too small, the size of the fuse portion 121 along the second direction is too small, the structural strength is poor, and the connecting piece 1 is easily bent and deformed under mechanical impact. If e is greater than 20 mm, the distance between the through hole 122 and the side of the connecting piece 1 is large. When the outer contour size of the connecting piece 1 is constant, the size occupied by the fuse portion 121 along the second direction is too large, the size of the through hole 122 along the second direction is too small, the fuse portion 121 is difficult to fuse, and the connecting piece 1 is difficult to play a fuse protection role when the battery cell is short-circuited. Therefore, by setting the minimum distance e from the edge of the through hole 122 to the side of the connecting piece 1 to a value in the range of 1.5 mm to 20 mm, it can be ensured that the connecting piece 1 has sufficient structural strength, avoiding the connecting piece 1 from bending and deforming under mechanical impact, thereby improving the reliability of the connecting piece 1, and it can also be ensured that the fuse part 121 can be blown in time when the battery cell is short-circuited, thereby improving the safety of the battery cell.

[0054] In one embodiment, further combined Figure 4 As shown, both sides of through hole 122 along the second direction are configured as rounded corners, and the radius of the circle where the rounded corners are located is R, where R = X / 2. By configuring both sides of through hole 122 along the second direction as rounded corners, and the radius R of the circle where the rounded corners are located being half of the dimension X of through hole 122 along the first direction, through hole 122 is oblong, and the outer contour of through hole 122 is smoothly transitioned, which improves structural strength and facilitates processing. Connecting piece 1 is not easily broken under mechanical impact, and has high reliability and safety.

[0055] Further integration Figure 4 As shown, the minimum distance e from the edge of through-hole 122 to the side of connecting piece 1 refers to the distance from the outline of through-hole 122 to the side of the adjacent connecting piece along a straight line along the second direction and passing through the center of the circle where the fillet is located. Specifically, through-hole 122 is located in the middle of fuse zone 120 along the second direction, and the distances from both sides of through-hole 122 to the side of each adjacent connecting piece 1 along the second direction are equal. The total projected area S of fuse portion 121 on a cross section passing through the center of through-hole 122 and perpendicular to the first direction is equal to twice the product of the minimum distance e from the edge of through-hole 122 to the side of connecting piece 1 and the dimension t of fuse portion 121 along the vertical direction, that is, S = 2et.

[0056] In addition, in other embodiments, further combined Figure 7As shown, the through hole 122 can also be set as a square hole, the long side of the square hole is parallel to the second direction and the short side is parallel to the first direction, and the distance from each position on the short side of the square hole to the adjacent side of the connecting piece is equal, and the distance is e.

[0057] The fuse test and mechanical vibration test were carried out on the connecting pieces with different parameter values of the connecting piece and the rubber coating matching structure. The test results are described below to verify that the connecting piece and the rubber coating matching structure of this embodiment can better play the role of thermal runaway protection.

[0058] The fuse blowing test is as follows: connect an external power supply, pass the corresponding current, perform a fuse blowing test, and observe the blowing condition and effective circuit breaking condition of the fuse part 121 on the connecting piece 1. The mechanical vibration test includes mechanical shock and battery pack vibration. The mechanical shock is as follows: the shock waveform is 7g, a 6ms half-sine waveform, and the axial direction is the Z direction; the number of shocks is 6 times in the positive and negative directions; the interval between two adjacent shocks is not less than 5 times the duration of the shock pulse. Battery pack vibration: using a sine wave sweep frequency, 7-18Hz: 10m / s 2 ; 18-30Hz: from 10m / s 2 Gradually reduce to 2m / s 2 , 30-50Hz: 2m / s 2 , single scan 15min, total 12 times, 3h.

[0059] Table 1 Test results of the implementation cases of the connecting pieces with different parameters

[0060]

[0061] Table 2 Comparative case test results of connectors with different parameters

[0062]

[0063] As can be seen from Table 1, for the connection piece and rubber coating structure of implementation case 1, all parameters are on the lower limit; in implementation case 2, S = 4mm 2 , X=1.9mm, X ratio Slightly smaller; in implementation case 3, S = 6 mm 2 , X=3mm, X is equal to In implementation case 4, S = 8 mm 2 , X=3.8mm, X ratio Slightly smaller; in implementation case 5, S = 10 mm 2 , X=5mm, X is equal to In Example 6, S = 12 mm 2 , X=5.9mm, X ratio Slightly smaller; that is, for the connection piece and the rubber coating matching structure of implementation cases 2 to 6, the value of X is closer to the upper limit, and the other parameters are closer to the lower limit; for the connection piece and the rubber coating matching structure of implementation case 7, all parameters are normal. For the connection piece and the rubber coating matching structure of implementation cases 1 to 7, each parameter is within the range specified in this application, and the dimension X of the through hole 122 along the first direction is within the range specified in this application of 0.5mm to The size of the covering portion 210 located on the lower side of the connecting piece 1 in the up and down directions is c within the range of 0.3mm to 3mm specified in this application. The connecting piece did not fail after the fuse melting test and the mechanical vibration test, and passed the test.

[0064] However, it can be seen from Table 2 that for the connection piece and the rubber coating matching structure of Comparative Case 1, X=0.48mm, which is less than 0.5mm, that is, the value of X exceeds the lower limit value specified in this application and is not within the range specified in this application. The other parameters are within the range specified in this application. After the fuse is blown, the through hole 122 is filled with the rubber coating layer, but an arc short circuit still occurs under high pressure; for the connection piece and the rubber coating matching structure of Comparative Cases 2 to Comparative Cases 6, the values of X are all greater than X exceeded the upper limit, and the fuse cracked after the vibration test. For the connecting piece and rubber coating matching structure of comparative case 7, the dimension c of the part of the coating 210 located on the lower side of the connecting piece 1 along the up and down directions was 0.27 mm, which was less than 0.3 mm, that is, the value of c exceeded the lower limit value specified in this application and was not within the range specified in this application. The other parameters were ok, and metal liquid dripped into the interior of the battery cell when the fuse was blown.

[0065] In summary, when the dimension X of the through hole 122 along the first direction is between 0.5 mm and When the dimension c of the portion of the covering portion 210 located on the lower side of the connecting piece 1 in the up-down direction is within the range of 0.3 mm to 3 mm specified in this application, it can avoid the arc short circuit phenomenon between the two half-pieces of the connecting piece under high voltage after the fuse portion 121 is melted, and ensure that the circuit can be completely cut off when the connecting piece 1 is melted. At the same time, it can ensure that the portion of the covering portion 210 located on the lower side of the connecting piece 1 has a certain thickness, ensuring that this portion will not be melted when the fuse portion 121 is melted, thereby preventing the melted liquid of the connecting piece 1 from dripping onto the electrode group and causing thermal runaway, thereby improving safety.

[0066] In addition, for the connecting piece and rubber coating structure of Comparative Example 8, b / X is equal to 1.18, which is less than 1.2, exceeding the lower limit specified in this application and not within the range specified in this application. Other parameters are normal. When the fuse blows, the rubber coating at the through hole falls off, and the connecting piece arcs continuously at high voltage, causing a short circuit. It can be seen that when the dimension b of the covering portion 210 along the first direction and the dimension X of the through hole 122 along the first direction are limited to meet the ratio relationship of 1.2≤b / X≤5, it can be ensured that the portion of the covering portion 210 overlapping the connecting piece body outside the through hole 122 can provide sufficient support for the filling portion 220, preventing the filling portion 220 from falling into the battery cell, thereby ensuring the insulation and isolation function of the rubber coating layer 2, ensuring that the circuit can be completely cut off when the connecting piece 1 blows, and improving safety.

[0067] For the connector and encapsulation structure in Comparative Example 9, a / t is 0.47, less than 0.5, exceeding the lower limit specified in this application and falling outside the specified range. Other parameters are acceptable, and the melted plastic fails to fill the upper barrier zone, resulting in a sustained short circuit caused by high-voltage arcing in the connector. This shows that when the vertical dimension a of the portion of the encapsulation 210 located above the connector 1 and the vertical dimension t of the fuse 121 satisfy the relationship of 0.5 ≤ a / t ≤ 5, it is ensured that when the fuse 121 blows, the melted plastic of the encapsulation 210 located above the connector 1 will fully fill the barrier zone formed by the melted fuse 121, acting as an insulating barrier and preventing sustained short circuits caused by high-voltage arcing.

[0068] For the connecting piece and encapsulation structure of Comparative Example 10, the distance d that the encapsulation 210 extends beyond the fuse 121 in the second direction is 0.29 mm, which is less than 0.3 mm, exceeding the lower limit specified in this application and falling outside the specified range. Other parameters are acceptable, and the melted plastic on the side does not fill the upper barrier zone, resulting in a sustained high-voltage arcing and short circuit. This indicates that when the distance d that the encapsulation 210 extends beyond the fuse 121 in the second direction is within the range of 0.3 mm to 3 mm, it is ensured that when the fuse 121 blows, the melted plastic on the encapsulation 210 located on the upper side of the connecting piece 1 will fully fill the barrier zone formed by the melted fuse 121, acting as an insulating barrier and preventing a sustained short circuit caused by high-voltage arcing.

[0069] In Comparative Example 11, the connecting piece and overmolding structure exhibited non-rounded corners on R1, normal X, and lower limits for the remaining parameters. After the vibration test, the fuse cracked. This indicates that when both sides of through hole 122 along the second direction are rounded, the outer contour of through hole 122 transitions smoothly, resulting in improved structural strength and ease of machining. Connecting piece 1 is less susceptible to breakage under mechanical impact.

[0070] According to another aspect of an embodiment of the present invention, a battery cell is provided, comprising: a housing, a pole group, a cover plate, and the aforementioned connecting piece and rubber encapsulation structure. The housing has an open end; the pole group is disposed within the housing and has a tab; the cover plate is disposed at the open end of the housing to seal the housing, and a pole is disposed on the cover plate; the pole connecting area 110 of the connecting piece 1 is connected to the pole, and the tab connecting area 130 is connected to the tab.

[0071] In one embodiment, further combined Figure 6 As shown, the connecting piece 1 is a boss structure, that is, the upper surface of the pole connection area 110 is higher than the upper surface of the tab connection area 130, and the lower surface of the pole connection area 110 is higher than the lower surface of the tab connection area 130, so as to make full use of the internal space of the battery cell, and the fuse area 120 is flush with the tab connection area 130.

[0072] The connecting piece 1 in the battery cell of this embodiment can be quickly melted when the battery cell is short-circuited without causing the risk of reconnection; it can also prevent the melted liquid of the connecting piece 1 and the encapsulating layer 2 from dripping onto the electrode group, ensuring the safe use of the battery cell.

[0073] According to another aspect of an embodiment of the present invention, a battery pack is provided, comprising: the above-mentioned battery cell. Preferably, there are multiple battery cells.

[0074] 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 connecting piece and rubber coating matching structure, characterized in that: include: A connecting piece, comprising a pole connection area, a fuse area, and a tab connection area sequentially connected along a first direction, wherein the fuse area comprises a fuse portion and a through hole, wherein the through hole has a dimension X along the first direction, and the total projected area of the fuse portion on a cross section passing through the center of the through hole and perpendicular to the first direction is S, wherein: The rubber layer has a covering portion and a filling portion, wherein the covering portion covers the surface of the fuse portion and extends beyond the fuse zone along a first direction, the filling portion is connected to the covering portion and fills the through hole, and the size of the portion of the covering portion located on the lower side of the connecting piece along the up and down direction is c, wherein 0.3mm≤c≤3mm.

2. The connecting piece and rubber coating matching structure according to claim 1, characterized in that: The covering portion covers the surface of the fuse portion and extends along a first direction toward both sides of the fuse zone. A dimension of the covering portion along the first direction is b, wherein 1.2≤b / X≤5.

3. The connecting piece and rubber coating matching structure according to claim 1, characterized in that: The total projected area S of the fuse portion on the cross section passing through the center of the through hole and perpendicular to the first direction is in the range of: 4mm 2 ≤S≤12mm 2 .

4. The connecting piece and rubber coating matching structure according to claim 1, characterized in that: The size of the fuse portion along the vertical direction is t, and the size of the portion of the covering portion located on the upper side of the connecting piece along the vertical direction is a, wherein 0.5≤a / t≤5.

5. The connecting piece and rubber coating matching structure according to claim 4, characterized in that: The dimension t of the fuse portion in the vertical direction has a value range of 0.6 mm ≤ t ≤ 2 mm.

6. The connecting piece and rubber coating matching structure according to any one of claims 1 to 5, characterized in that: The covering portion protrudes from the melting zone along a second direction, and the distance d by which the covering portion extends beyond the melting zone in the second direction has a value range of 0.3 mm ≤ d ≤ 3 mm, wherein the second direction is perpendicular to the first direction in the plane where the upper surface of the connecting piece is located.

7. The connecting piece and rubber coating matching structure according to claim 6, characterized in that: Along the second direction, the minimum distance from the edge of the through hole to the side of the connecting piece is e, where 1.5 mm ≤ e ≤ 20 mm.

8. The connecting piece and rubber coating matching structure according to claim 6, characterized in that: Both sides of the through hole along the second direction are configured as rounded corners, and the radius of the circle where the rounded corners are located is R, wherein R=X / 2.

9. A battery cell, characterized in that: include: a housing having an open end; A pole group is arranged in the shell, and the pole group has pole ears; a cover plate, arranged at the open end of the shell to close the shell, and a pole is arranged on the cover plate; The connecting piece and rubber-encapsulated matching structure according to any one of claims 1 to 8, wherein the pole connection area of the connecting piece is connected to the pole and the tab connection area is connected to the tab.

10. A battery pack, characterized in that: include: The battery cell according to claim 9.

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