Connecting piece, battery and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a connecting piece, a battery and a battery pack. The tab connecting part is connected with the pole connecting part, a reinforcing rib is formed on the tab connecting part in a protruding manner, the volume occupied by the reinforcing rib is V1, the volume occupied by the tab connecting part is V0, and V1 is larger than or equal to 1 / 3 * V0 and smaller than or equal to 1 / 2 * V0. The reinforcing ribs are arranged on the tab connecting part, so that the structural strength of the tab connecting part is improved, the bending angle of the tab connecting part is reduced after the tab connecting part and the tab are welded, and the situation that the tab connecting part is bent to a large extent under the tension of the tab to puncture the diaphragm is avoided; safety accidents such as short circuit and thermal runaway of the battery are avoided, so that the safety performance of the battery is improved; moreover, the volume ratio of the reinforcing rib to the tab connecting part is limited, so that the structural strength of the tab connecting part is effectively improved by the reinforcing rib, and the influence on welding with the tab caused by excessive occupation of the tab connecting part is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a connecting piece, a battery and a battery pack. Background Art

[0002] As lithium-ion battery technology matures, it is widely used in electric vehicles as a new type of power battery, and the safety requirements for batteries are increasing. In batteries, connecting plates are usually used to electrically connect the electrode group and the pole to lead the electrical energy of the pole group to the outside. Specifically, the connecting plates are connected to the pole by laser welding and to the pole tabs of the pole group by ultrasonic welding. However, after the connecting plates are welded to the pole tabs, the tension of the pole tabs can easily cause the connecting plates to bend, which can then cause the connecting plates to pierce the diaphragm of the pole group, resulting in safety accidents such as battery short circuit and thermal runaway. Summary of the Invention

[0003] In view of this, the present invention provides a connecting piece, a battery and a battery pack to solve the problem in the prior art that the connecting piece is easily bent under the tension of the tab, which in turn causes the connecting piece to pierce the diaphragm of the electrode group, resulting in safety accidents such as battery short circuit and thermal runaway.

[0004] In a first aspect, the present invention provides a connecting piece, comprising: a pole connecting portion; a tab connecting portion, connected to the pole connecting portion, wherein a reinforcing rib is protruding from the tab connecting portion, the volume occupied by the reinforcing rib is V1, and the volume occupied by the tab connecting portion is V0, satisfying 1 / 3×V0≤V1≤1 / 2×V0.

[0005] Beneficial effects: By arranging reinforcing ribs on the tab connection part, the structural strength of the tab connection part is improved. After the tab connection part is welded to the tab, the bending angle of the tab connection part is reduced, so that the tab connection part is prevented from being bent to a large extent by the tension of the tab and causing puncture of the diaphragm, thereby avoiding the occurrence of safety accidents such as battery short circuit and thermal runaway, thereby improving the safety performance of the battery; and, by limiting the volume ratio between the reinforcing rib and the tab connection part, while the reinforcing rib effectively improves the structural strength of the tab connection part, it avoids occupying too much of the tab connection part and affecting the welding with the tab.

[0006] In an optional embodiment, the pole tab connection portion includes a base sheet and a welding sheet, the base sheet is connected to the pole connection portion, the welding sheet is connected to the base sheet, one welding sheet is provided or several welding sheets are provided at intervals, and each welding sheet is provided with at least one reinforcing rib.

[0007] In an optional embodiment, along the y direction, the width of the welding sheet is B, and the width of the reinforcing rib is A, satisfying 1 / 6×B≤A≤1 / 3×B.

[0008] Beneficial effect: while the reinforcing ribs effectively improve the structural strength of the tab connection portion, the ribs are prevented from occupying too much of the tab connection portion in the width direction, thereby affecting the welding with the tab.

[0009] In an optional embodiment, the width A of the reinforcing rib satisfies 1.5 mm ≤ A ≤ 3 mm; and / or the width B of the welding sheet satisfies 8 mm ≤ B ≤ 10 mm.

[0010] In an optional embodiment, the base sheet and the pole connecting portion are transitionally connected via a bent portion, so that the tab connecting portion and the pole connecting portion are relatively spaced apart along the z direction.

[0011] In an optional embodiment, along the z direction, the inner height of the bending portion is E, and the thickness of the tab connection portion is C, satisfying 2.5×C≤E≤8×C; and / or, the inner height E of the bending portion satisfies 2.5mm≤E≤4mm.

[0012] Beneficial effect: ensuring that the tab connection has an appropriate distance between the pole and the pole group, and both the pole and the pole group, while facilitating the welding of the tabs and the tab connection, and avoiding the tab connection and the pole group from contacting and puncturing the diaphragm to cause safety problems.

[0013] In an optional embodiment, along the x-direction, the length of the tab connection portion is F, the length of the reinforcement rib is G, satisfying 1 / 3×F≤G≤F; and / or, along the z-direction, the thickness of the tab connection portion is C, the total thickness corresponding to the reinforcement rib is D, satisfying 1 / 3×D≤C≤1 / 2×D.

[0014] Beneficial effect: By limiting the length of the reinforcing ribs, the reinforcing ribs can effectively improve the structural strength of the tab connection;

[0015] By limiting the thickness of the reinforcing ribs, the reinforcing ribs can be easily processed and formed while effectively improving the structural strength of the tab connection.

[0016] In an optional embodiment, the length F of the tab connection portion satisfies 30mm≤F≤80mm; and / or the thickness C of the tab connection portion satisfies 0.5mm≤C≤1mm; and / or the thickness D of the reinforcing rib satisfies 1.5mm≤D≤2.5mm.

[0017] In a second aspect, the present invention further provides a battery comprising the above-mentioned connecting piece.

[0018] In a third aspect, the present invention further provides a battery pack comprising the above-mentioned battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 A top view of a connecting piece according to an embodiment of the present invention;

[0021] Figure 2 for Figure 1 A cross-sectional view of the connecting piece shown in direction II;

[0022] Figure 3 for Figure 1 The schematic diagram of the structure of the connecting piece shown is when the bending portion is not bent;

[0023] Figure 4 for Figure 3 A top view of the connecting piece shown;

[0024] Figure 5 A top view of another connecting piece according to an embodiment of the present invention;

[0025] Figure 6 for Figure 5 A top view of the connecting piece shown when the bent portion is not bent;

[0026] Figure 7 This is a schematic structural diagram of a connecting piece and an electrode group according to an embodiment of the present invention;

[0027] Figure 8 for Figure 7 A top view of the connecting piece and the pole group shown;

[0028] Figure 9 for Figure 8 A partial cross-sectional view of the connecting piece and the electrode group in the JJ direction is shown;

[0029] Figure 10 This is a structural diagram of a connecting piece and a cover plate according to an embodiment of the present invention;

[0030] Figure 11 for Figure 10 The diagram shows the structure of the connecting piece and the cover plate when the bent portion is not bent.

[0031] Description of reference numerals:

[0032] 1. Pole connection part; 2. Tab connection part; 21. Base sheet; 22. Welding sheet; 3. Reinforcement rib; 4. Bending part; 10. Pole group; 101. Tab; 20. Cover plate. DETAILED DESCRIPTION

[0033] 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.

[0034] The following combination Figures 1 to 11 , describing embodiments of the present invention.

[0035] According to an embodiment of the present invention, on the one hand, a connecting piece is provided, including: a pole connecting portion 1; a tab connecting portion 2, which is connected to the pole connecting portion 1, and a reinforcing rib 3 is protruded from the tab connecting portion 2, the volume occupied by the reinforcing rib 3 is V1, and the volume occupied by the tab connecting portion 2 is V0, satisfying 1 / 3×V0≤V1≤1 / 2×V0.

[0036] By providing a reinforcing rib 3 on the tab connection part 2, the structural strength of the tab connection part 2 is improved. After the tab connection part 2 is welded to the tab 101, the bending angle of the tab connection part 2 is reduced to avoid the tab connection part 2 being bent to a large extent by the tension of the tab 101, thereby piercing the diaphragm, thereby avoiding the occurrence of safety accidents such as battery short circuit and thermal runaway, thereby improving the safety performance of the battery; and, by limiting the volume ratio between the reinforcing rib 3 and the tab connection part 2, while the reinforcing rib 3 effectively improves the structural strength of the tab connection part 2, it avoids occupying too much of the tab connection part 2 and affecting the welding with the tab 101.

[0037] It is worth noting that the volume occupied by the tab connection portion 2 is the volume of the space occupied by the tab connection portion 2. For example, if the tab connection portion 2 is a rectangular plate structure, the volume occupied by the tab connection portion 2 is the size occupied by the length direction of the tab connection portion 2 × the size occupied by the width direction × the size occupied by the thickness direction, that is, V0 = F × 2 × B × C (please refer to Figure 2 and Figure 4 ); The volume occupied by the reinforcement rib 3 is the volume of the space occupied by the reinforcement rib 3. For example, if the reinforcement rib 3 is a long strip structure, the volume occupied by the reinforcement rib 3 is the size occupied by the reinforcement rib 3 in the length direction × the size occupied by the width direction × the size occupied by the thickness direction, that is, V1 = G × A × D (please refer to Figure 2 and Figure 4 ).

[0038] It should be noted that if the volume occupied by the reinforcement rib 3 on the tab connection part 2 is too small, that is, the volume of the reinforcement rib 3 is too small, the effect of the reinforcement rib 3 on improving the structural strength of the tab connection part 2 is not obvious. After the tab connection part 2 is welded to the tab 101, under the tension of the tab 101, the possibility of the tab connection part 2 bending is still too great, resulting in the battery still having safety problems such as short circuit and thermal runaway; if the volume occupied by the reinforcement rib 3 on the tab connection part 2 is too large, that is, the volume of the reinforcement rib 3 is too large, the remaining part of the tab connection part 2 that can be welded to the tab 101 is too small, and sufficient welding area cannot be provided, which affects the welding strength and overcurrent capability.

[0039] In one embodiment, Figures 3 to 6 As shown, the pole tab connection part 2 includes a basic sheet 21 and a welding sheet 22. The basic sheet 21 is connected to the pole connection part 1, and the welding sheet 22 is connected to the basic sheet 21. One welding sheet 22 is provided or several welding sheets 22 are provided at intervals, and each welding sheet 22 is correspondingly provided with at least one reinforcing rib 3.

[0040] It is worth noting that the welding sheet 22 is used to be welded to the tab 101. Therefore, the reinforcing rib 3 is provided at least corresponding to the welding sheet 22, thereby improving the structural strength of the welding sheet 22 and preventing the welding sheet 22 from bending under the tensile force of the tab 101 after being welded to the tab 101. Specifically, the reinforcing rib 3 can be provided only on the welding sheet 22, or on both the welding sheet 22 and the base sheet 21. Preferably, in this embodiment, as Figures 1 to 6 As shown, the reinforcing ribs 3 are extended along the x-direction and provided on the welding sheet 22 and the base sheet 21 .

[0041] It should be noted that, in this embodiment, Figures 1 to 6 As shown, each basic sheet 21 is connected to two welding sheets 22 , and each welding sheet 22 is correspondingly provided with a reinforcing rib 3 .

[0042] Of course, in other alternative embodiments, each base sheet 21 may be connected to a plurality of welded sheets 22, and / or each welded sheet 22 may be provided with a plurality of reinforcing ribs 3. It should be noted that the volume occupied by the tab connection portion 2 is the sum of the volumes occupied by the base sheet 21 and all the welded sheets 22, and the volume occupied by the reinforcing rib 3 is the sum of the volumes occupied by all the reinforcing ribs 3.

[0043] In one embodiment, Figure 1 、 Figures 4 to 6As shown, along the y direction, the width of the welding sheet 22 is B, and the width of the reinforcing rib 3 is A, satisfying 1 / 6×B≤A≤1 / 3×B. This arrangement effectively improves the structural strength of the tab connection portion 2 while preventing the reinforcing rib 3 from occupying too much of the tab connection portion 2 in the width direction and affecting welding with the tab 101.

[0044] It is worth noting that if the width of the reinforcing rib 3 is too small, the reinforcing rib 3 will not significantly improve the structural strength of the tab connection part 2. After the tab connection part 2 is welded to the tab 101, the possibility of the tab connection part 2 bending under the tension of the tab 101 is still too high, resulting in the battery still having safety problems such as short circuit and thermal runaway. Please refer to Figure 9 Since the tab 101 is connected to the welding sheet 22 along the y direction, if the width of the reinforcing rib 3 is too large, the remaining portion of the welding sheet 22 that can be connected to the tab 101 will be too small, resulting in the welding sheet 22 being unable to provide sufficient welding area, affecting the welding strength and overcurrent capacity.

[0045] Specifically, the width A of the reinforcing rib 3 satisfies 1.5 mm ≤ A ≤ 3 mm, and the width B of the welding sheet 22 satisfies 8 mm ≤ B ≤ 10 mm.

[0046] In one embodiment, Figures 1 to 6 As shown, the base sheet 21 and the pole connecting portion 1 are transitionally connected via the bent portion 4 so that the tab connecting portion 2 and the pole connecting portion 1 are arranged relatively spaced apart along the z direction.

[0047] Further, such as Figure 2 As shown, along the z direction, the inner height of the bent portion 4 is E, and the thickness of the tab connection portion 2 is C, satisfying 2.5×C≤E≤8×C. The inner height E of the bent portion 4 satisfies 2.5mm≤E≤4mm. This arrangement ensures that the tab connection portion 2 has an appropriate distance between the pole and the pole group 10, and both the pole and the pole group 10. While facilitating welding of the tab 101 to the tab connection portion 2, it also prevents the tab connection portion 2 from contacting the pole group 10 and puncturing the diaphragm, causing safety issues.

[0048] It is worth noting that, based on the pole connection part 1, if the inner height of the bending part 4 is too small, that is, the distance between the pole lug connection part 2 and the pole connection part 1 is too close, the distance between the pole lug connection part 2 and the cover plate 20 will be too close, which is inconvenient for the connection between the pole lug 101 and the pole lug connection part 2, and it is easy to cause the pole lug 101 to contact the cover plate 20, posing a safety risk; if the inner height of the bending part 4 is too large, that is, the distance between the pole lug connection part 2 and the pole connection part 1 is too far, the distance between the pole lug connection part 2 and the pole group 10 will be too close, the pole lug connection part 2 will easily come into contact with the pole group 10 and pierce the diaphragm, resulting in safety problems such as short circuit and thermal runaway.

[0049] It should be noted that during the processing of the connecting piece, before the bending portion 4 is bent, a pre-crease can be set at the center position of the area corresponding to the bending portion 4, so as to ensure that the bending center line always remains at the center position of the area corresponding to the bending portion 4 when the bending portion 4 is bent, and to ensure that the pole ear connection portion 2 is not tilted after bending, thereby preventing the pole ear connection portion 2 from being inserted into the pole group 10 and piercing the diaphragm to cause safety problems. At the same time, it also prevents the pole ear connection portion 2 from overlapping with the outer shell area such as the cover plate 20 to cause internal short circuit, thereby effectively improving the safety performance of the battery.

[0050] In one embodiment, Figures 4 to 6 As shown, along the x direction, the length of the tab connection portion 2 is F, and the length of the rib 3 is G, satisfying 1 / 3×F≤G≤F. By limiting the length of the rib 3, the rib 3 can effectively improve the structural strength of the tab connection portion 2.

[0051] It is worth noting that if the length of the reinforcing rib 3 is too short, the reinforcing rib 3 will not significantly improve the structural strength of the tab connection portion 2. After the tab connection portion 2 is welded to the tab 101, the possibility of the tab connection portion 2 bending under the tensile force of the tab 101 is still too high, resulting in safety issues such as short circuit and thermal runaway in the battery. Specifically, the length of the reinforcing rib 3 can be specifically set according to the length of the welding sheet 22. Preferably, the length of the reinforcing rib 3 is greater than the length of the welding sheet 22, that is, the reinforcing rib 3 can extend from the welding sheet 22 to the base sheet 21. Optionally, the length of the reinforcing rib 3 can be equal to the length of the tab connection portion 2, that is, G = F, in which case the reinforcing rib 3 is arranged along the entire length of the tab connection portion 2.

[0052] Optionally, in this embodiment, if Figures 1 to 6 As shown, along the x direction, the distance from the end of the reinforcing rib 3 to the edge of the corresponding tab connecting portion 2 is H, which satisfies 3mm≤H≤10mm.

[0053] In one embodiment, Figure 2 As shown, along the z direction, the thickness of the tab connection portion 2 is C, and the corresponding total thickness at the reinforcing rib 3 is D, satisfying 1 / 3×D≤C≤1 / 2×D. By limiting the thickness of the reinforcing rib 3, the reinforcing rib 3 can be easily processed and formed while effectively improving the structural strength of the tab connection portion 2.

[0054] It is worth noting that the reinforcing rib 3 can be formed on the tab connection portion 2 using a stamping process. If the thickness of the reinforcing rib 3 is too small, the reinforcing rib 3 will not significantly improve the structural strength of the tab connection portion 2. After the tab connection portion 2 is welded to the tab 101, the possibility of the tab connection portion 2 bending under the tensile force of the tab 101 is still too high, resulting in safety issues such as short circuit and thermal runaway in the battery. If the thickness of the reinforcing rib 3 is too large, that is, the reinforcing rib 3 protrudes too much from the tab connection portion 2, it will be difficult to process and form the reinforcing rib 3, and it will easily result in the reinforcing rib 3 having too low strength and being prone to breakage.

[0055] Specifically, the length F of the tab connection portion 2 satisfies 30 mm ≤ F ≤ 80 mm, the thickness C of the tab connection portion 2 satisfies 0.5 mm ≤ C ≤ 1 mm, and the thickness D of the reinforcing rib 3 satisfies 1.5 mm ≤ D ≤ 2.5 mm.

[0056] It is worth noting that the cross section of the reinforcing rib 3 perpendicular to the x-direction is U-shaped, semicircular, or semi-elliptical.

[0057] It should be noted that, according to the tensile test, the tensile force of the connecting piece of this embodiment is increased from 260N to 320N compared with the connecting piece without the reinforcing rib 3, which greatly improves the structural strength of the connecting piece.

[0058] The following observation tests were conducted on connecting tabs of different sizes after being welded to the tabs. The results for the Examples and Comparative Examples are shown in Table 1. "Whether the separator was punctured" was determined by performing a Hi-Pot short-circuit test on the battery; "whether welding was affected" was determined by observing whether there was space for the welding track on the connecting tab during the welding process. Specifically, the Examples refer to connecting tabs that met the requirements of these Examples, while the Comparative Examples refer to connecting tabs that did not meet the requirements of these Examples.

[0059] Table 1 Observation test results after welding the connecting piece and the tab

[0060]

[0061] It can be seen from Table 1 that in Examples 1 to 4, 1 / 3≤V1 / V0≤1 / 2 is satisfied. Therefore, the connecting pieces of Examples 1 to 4 have sufficient structural strength and will not affect the welding with the tabs.

[0062] It can be seen from Table 1 that in Comparative Examples 1 to 4, V1 / V0 is less than 1 / 3, resulting in the structural strength of the connecting piece still being weak. There is still a risk of puncturing the diaphragm after the tab and the connecting piece are welded, resulting in a short circuit problem in the battery.

[0063] As can be seen from Table 1, in Comparative Examples 5 and 6, V1 / V0>1 / 2, resulting in a smaller space on the connecting piece for welding with the tab. When the connecting piece and the tab are welded, the connecting piece cannot accommodate the welding track, affecting the welding of the connecting piece and the tab.

[0064] According to another aspect of an embodiment of the present invention, a battery is provided, comprising the above-mentioned connecting piece.

[0065] According to another aspect of the embodiments of the present invention, a battery pack is provided, comprising the above-mentioned battery.

[0066] 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, characterized in that: include: Pole connection part; The tab connection portion is connected to the pole connection portion, and a reinforcing rib is protruded from the tab connection portion. The volume occupied by the reinforcing rib is V1, and the volume occupied by the tab connection portion is V0, satisfying 1 / 3×V0≤V1≤1 / 2×V0.

2. The connecting piece according to claim 1, characterized in that The pole tab connection portion includes a base sheet and a welding sheet. The base sheet is connected to the pole connection portion, and the welding sheet is connected to the base sheet. One or several welding sheets are provided at intervals, and each welding sheet is correspondingly provided with at least one reinforcing rib.

3. The connecting piece according to claim 2, characterized in that: Along the y direction, the width of the welding sheet is B, and the width of the reinforcing rib is A, satisfying 1 / 6×B≤A≤1 / 3×B.

4. The connecting piece according to claim 3, characterized in that The width A of the reinforcing rib satisfies 1.5 mm ≤ A ≤ 3 mm; and / or, The width B of the welding sheet satisfies 8mm≤B≤10mm.

5. The connecting piece according to any one of claims 2 to 4, characterized in that The base sheet and the pole connecting portion are transitionally connected via a bent portion, so that the tab connecting portion and the pole connecting portion are relatively spaced apart along the z direction.

6. The connecting piece according to claim 5, characterized in that Along the z direction, the inner height of the bent portion is E, the thickness of the tab connection portion is C, and 2.5×C≤E≤8×C is satisfied; and / or, The inner height E of the bent portion satisfies 2.5 mm ≤ E ≤ 4 mm.

7. The connecting piece according to any one of claims 1 to 4, characterized in that Along the x-direction, the length of the tab connection portion is F, the length of the reinforcing rib is G, and the relationship 1 / 3×F≤G≤F is satisfied; and / or, Along the z direction, the thickness of the tab connection portion is C, and the total thickness corresponding to the reinforcing rib is D, satisfying 1 / 3×D≤C≤1 / 2×D.

8. The connecting piece according to claim 7, characterized in that: The length F of the tab connection portion satisfies 30 mm ≤ F ≤ 80 mm; and / or, The thickness C of the tab connection portion satisfies 0.5 mm ≤ C ≤ 1 mm; and / or, The thickness D of the reinforcing rib satisfies 1.5 mm ≤ D ≤ 2.5 mm.

9. A battery, characterized in that: The connecting piece comprises the connecting piece according to any one of claims 1 to 8.

10. A battery pack, characterized in that: A battery comprising the battery of claim 9.

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