Testing structure for overcurrent at laser welding position of connecting sheet and pole

Abstract

The utility model relates to a structure for testing overcurrent at a laser welding position of a connecting piece and a pole, which comprises a lithium ion battery, a first busbar is welded at the top of the lithium ion battery through laser, the first busbar is connected with the connecting piece, the connecting piece and the pole of a cover plate are welded through laser to form a laser welding mark, and the laser welding mark is connected with one end of a temperature sensing line. The other end of the temperature sensing line is connected with the battery testing system, and the pole of the cover plate is connected with the second busbar which is connected with the battery testing system. According to the testing structure, the reversed cover plate is additionally arranged on the basis of an original lithium ion battery, the top of the pole of the cover plate is in laser welding with the connecting piece, the bottom of the pole of the cover plate is in laser welding with the busbar, and one end of the temperature sensing line is connected with a laser welding mark formed by laser welding of the pole and the connecting piece. Over-current is judged through temperature rise at the laser welding printing position, convenience and simplicity are achieved, and it is avoided that temperature rise measurement is inconvenient due to the fact that the laser welding printing positions of the connecting piece and the bottom of the pole column are located in the battery cell.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium-ion battery cores, and in particular relates to an overcurrent testing structure at a laser welding mark between a connecting piece and a pole. Background Art

[0002] Square aluminum shell lithium iron phosphate battery cells are widely used in the field of energy storage. As the capacity of the battery cells becomes larger and larger, the shortcoming of overcurrent gradually emerges.

[0003] Generally speaking, the shortest board for overcurrent is the laser welding point between the connecting piece and the bottom of the pole, and the overcurrent capacity is generally judged by temperature rise. If the temperature rise is too high, the overcurrent capacity is insufficient. Because the laser welding point between the connecting piece and the bottom of the pole is inside the battery cell, it is inconvenient to measure the temperature rise, which makes it difficult for us to evaluate the overcurrent.

[0004] In summary, a relatively convenient and reliable structure is needed to measure the temperature rise at the laser welding point between the connecting piece and the bottom of the pole, so as to evaluate the overcurrent capacity. Summary of the invention

[0005] The utility model aims to provide a testing structure for overcurrent at the laser welding mark of a connecting piece and a pole, which can conveniently and quickly test the overcurrent at the laser welding mark of a connecting piece and a pole.

[0006] The technical solution adopted by the utility model to solve the above-mentioned problem is: a test structure for overcurrent at the laser welding mark of a connecting plate and a pole, comprising a first lithium-ion battery, two first bus bars are laser-welded symmetrically on the top of the first lithium-ion battery, the two first bus bars are respectively connected to the connecting plate, the connecting plate and the pole of the cover plate are laser-welded to form a laser welding mark, the laser welding mark is connected to one end of a temperature sensing line, the other end of the temperature sensing line is connected to a battery testing system, the pole of the cover plate is also connected to a second bus bar, and the second bus bar is also connected to the battery testing system.

[0007] Preferably, the test structure further comprises a second lithium-ion battery, and two third bus bars are laser-welded symmetrically on the top of the second lithium-ion battery, and the third bus bars are connected to the connecting piece.

[0008] Preferably, the first lithium-ion battery comprises a battery casing, a battery cell accommodated in the battery casing, and a battery cover plate sealed and assembled on the battery casing.

[0009] Preferably, the two first bus bars are respectively connected to the connecting pieces by screws.

[0010] Preferably, the third bus is screwed to the connecting piece.

[0011] Preferably, the second bus is connected to a current line of an external battery testing system via screws.

[0012] Preferably, the thickness of the first busbar and the second busbar is ≥2 mm; the first busbar and the second busbar are copper-aluminum composite busbars.

[0013] Preferably, a temperature probe is provided at one end of the temperature sensing line, and one end of the temperature sensing line is connected to the laser weld mark via the temperature probe, and the temperature probe is bonded to the laser weld mark via a high-temperature tape.

[0014] Preferably, the second lithium-ion battery comprises a battery casing, a battery cell accommodated in the battery casing, and a battery cover plate sealed and assembled on the battery casing.

[0015] Preferably, the thickness of the third busbar is ≥2 mm; and the third busbar is a copper-aluminum composite busbar.

[0016] Preferably, the connecting piece is a soft connecting piece or a hard connecting piece.

[0017] Compared with the prior art, the advantages of the utility model are:

[0018] The utility model adds a reverse cover plate on the basis of the original lithium ion battery, so that the top of the pole of the cover plate is laser welded with the connecting piece, the bottom of the pole of the cover plate is laser welded with the second bus, and one end of the temperature sensing line is connected to the laser welding mark (formed by laser welding of the connecting piece and the pole of the cover plate) through the temperature probe, and the other end of the temperature sensing line is connected to the battery testing system. Overcurrent is judged by the temperature rise at the laser welding mark, which is convenient and simple, and avoids the defect of inconvenient temperature rise measurement caused by the connection piece and the pole laser welding mark being located inside the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the test structure for overcurrent at the laser welding mark between the connecting piece and the pole in Example 1 of the utility model.

[0020] Figure 2 It is a schematic diagram of the test structure for overcurrent at the laser welding mark between the connecting piece and the pole in Example 2 of the utility model.

[0021] Among them: 1.1 is the first lithium-ion battery, 1.2 is the second lithium-ion battery, 2.1 is the first bus, 2.2 is the second bus, 2.3 is the third bus, 3 is the connecting piece, 4 is the cover plate, 5 is the laser welding print, 6 is the temperature sensing line, 7 is the screw, and 8 is the current line. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail below in conjunction with the accompanying drawings. Example 1

[0023] like Figure 1 As shown, it is a schematic diagram of the test structure of overcurrent at the laser welding mark between the connecting piece and the pole in this embodiment.

[0024] A test structure for overcurrent at the laser welding mark of a connecting piece and a pole comprises a first lithium-ion battery 1.1, wherein the first lithium-ion battery 1.1 comprises a battery shell, a battery cell accommodated in the battery shell, and a battery cover plate sealed and assembled on the battery shell.

[0025] Two first busbars 2.1 are symmetrically laser-welded on the top of the first lithium-ion battery 1.1. The two first busbars 2.1 are respectively connected to the connecting piece 3 via screws 7. The connecting piece 3 and the pole of the cover plate 4 (which adopts the folding ear process) are laser-welded to form a laser welding mark 5. The laser welding mark 5 is connected to one end of the temperature sensing line 6. The end of the temperature sensing line 6 connected to the laser welding mark 5 is provided with a temperature probe, that is, one end of the temperature sensing line 6 is connected to the laser welding mark 5 via the temperature probe, and the temperature probe is bonded to the laser welding mark 5 via a high-temperature tape. The other end of the temperature sensing line 6 is connected to the battery testing system. The pole of the cover plate 4 is also laser-welded with a second busbar 2.2, and the second busbar 2.2 is connected to the current line 8 of the external battery testing system through screws; wherein the thickness of the first busbar 2.1 and the second busbar 2.2 is 2 mm; the first busbar 2.1 and the second busbar 2.2 are copper-aluminum composite busbars, and the connecting piece 3 is a soft connecting piece.

[0026] It can be seen that the top of the pole of the cover plate 4 is laser welded to the connecting piece 3, and the bottom of the pole of the cover plate 4 is laser welded to the second bus 2.2. The utility model adds a reversed cover plate 4 on the basis of the original lithium-ion battery, so that the top of the pole of the cover plate 4 is laser welded to the connecting piece 3, and the bottom of the pole of the cover plate 4 is laser welded to the second bus 2.2, and one end of the temperature sensing line 6 is connected to the laser welding mark 5 (formed by laser welding of the connecting piece 3 and the pole of the cover plate 4) through the temperature probe, and the other end of the temperature sensing line 6 is connected to the battery testing system. The overcurrent can be judged by the temperature rise at the laser welding mark 5, which is convenient and simple, and avoids the defect of inconvenient temperature rise measurement caused by the connection piece and the pole laser welding mark inside the battery cell.

[0027] In practical applications, the second bus 2.2 is connected to the battery testing system, the probe of the temperature sensing line 6 of the battery testing system is connected to the laser weld mark 5, and the lithium-ion battery 1.1 is subjected to a charge and discharge cycle test with a certain current at an ambient temperature of 25±2°C. After the test, the initial charging temperature, the final charging temperature, the initial discharging temperature, and the final discharging temperature of each cycle are recorded, and then the charging temperature rise and the discharging temperature rise of each cycle are calculated. The maximum charging temperature rise and the maximum discharging temperature rise are used to determine whether the overcurrent at the laser weld mark 5 meets the requirements. Example 2

[0028] like Figure 2 As shown, it is a schematic diagram of the test structure of overcurrent at the laser welding mark between the connecting piece and the pole in this embodiment.

[0029] A test structure for overcurrent at the laser welding mark of a connecting piece and a pole comprises a first lithium-ion battery 1.1, wherein the first lithium-ion battery 1.1 comprises a battery shell, a battery cell accommodated in the battery shell, and a battery cover plate sealed and assembled on the battery shell.

[0030] Two first busbars 2.1 are symmetrically laser-welded on the top of the first lithium-ion battery 1.1. The two first busbars 2.1 are respectively connected to the connecting piece 3 via screws 7. The connecting piece 3 and the pole of the cover plate 4 (which adopts the butterfly welding process) are laser-welded to form a laser weld mark 5. The laser weld mark 5 is connected to one end of a temperature sensing line 6. A temperature probe is provided at one end of the temperature sensing line 6. One end of the temperature sensing line 6 is connected to the laser weld mark 5 via the temperature probe. The temperature probe is bonded to the laser weld mark 5 via a high-temperature tape. The other end of the temperature sensing line 6 is connected to a battery testing system.

[0031] The pole of the cover plate 4 is also connected to a second busbar 2.2, which is connected to a current line 8 of an external battery testing system via screws, and the second busbar 2.2 is perpendicular to the first busbar 2.1.

[0032] The test structure also includes a second lithium-ion battery 1.2, which includes a battery housing, a battery cell contained in the battery housing, and a battery cover sealed and assembled on the battery housing. The first lithium-ion battery 1.1, the cover 4, and the second lithium-ion battery 1.2 are arranged in parallel, and the cover 4 is located between the first lithium-ion battery 1.1 and the second lithium-ion battery 1.2. Two third busbars 2.3 are laser-welded symmetrically on the top of the second lithium-ion battery 1.2, and the third busbars 2.3 are connected to the connecting piece 3.

[0033] The thickness of the first busbar 2.1, the second busbar 2.2 and the third busbar 2.3 are all 2 mm; the first busbar 2.1, the second busbar 2.2 and the third busbar 2.3 are all copper-aluminum composite busbars; and the connecting piece 3 is a hard connecting piece.

[0034] The specific operation in practical application is the same as that in Example 1.

[0035] In addition to the above embodiments, the present invention also includes other implementation modes. Any technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. A test structure for overcurrent at a laser weld mark between a connecting piece and a pole, comprising a first lithium-ion battery (1.1), characterized in that: Two first busbars (2.1) are symmetrically laser-welded on the top of the first lithium-ion battery (1.1); the two first busbars (2.1) are respectively connected to a connecting piece (3); the connecting piece (3) and a pole of a cover plate (4) are laser-welded to form a laser weld mark (5); the laser weld mark (5) is connected to one end of a temperature sensing line (6); the other end of the temperature sensing line (6) is connected to a battery testing system; the pole of the cover plate (4) is also connected to a second busbar (2.2); and the second busbar (2.2) is also connected to the battery testing system.

2. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: The test structure also includes a second lithium-ion battery (1.2), two third busbars (2.3) are laser-welded symmetrically on the top of the second lithium-ion battery (1.2), and the third busbars (2.3) are connected to the connecting sheet (3).

3. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: The first lithium-ion battery (1.1) comprises a battery casing, a battery cell accommodated in the battery casing, and a battery cover plate sealed and assembled on the battery casing.

4. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: The two first busbars (2.1) are respectively connected to the connecting piece (3) via screws (7).

5. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: The thickness of the first busbar (2.1) and the second busbar (2.2) is ≥2 mm; the first busbar (2.1) and the second busbar (2.2) are copper-aluminum composite busbars.

6. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: One end of the temperature sensing line (6) is provided with a temperature probe, and one end of the temperature sensing line (6) is connected to the laser weld mark (5) via the temperature probe, and the temperature probe is bonded to the laser weld mark (5) via a high-temperature adhesive tape.

7. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 2 is characterized in that: The second lithium-ion battery (1.2) comprises a battery casing, a battery cell accommodated in the battery casing, and a battery cover plate sealed and assembled on the battery casing.

8. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 2 is characterized in that: The thickness of the third busbar (2.3) is ≥2 mm; and the third busbar (2.3) is a copper-aluminum composite busbar.

9. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 2 is characterized in that: The third busbar (2.3) is connected to the connecting piece (3) via screws (7).

10. The overcurrent test structure at the laser welding mark of the connecting piece and the pole according to claim 1 is characterized in that: The connecting piece (3) is a soft connecting piece or a hard connecting piece.

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