A short circuit test structure for lithium ion batteries

Abstract

The utility model discloses a kind of lithium ion battery short circuit test structures, comprising: workbench, the battery cell placed on workbench, the main compression assembly and head compression assembly for compressing different parts of battery cell, main compression assembly is used to compress the middle area of battery cell, main compression assembly includes the compression plate being located in the upper of battery cell and the first cylinder being located on compression plate, and the first cylinder is used to drive compression plate to compress the middle area of battery cell downward;Head compression assembly has two, two head compression assemblies are used to compress the two head positions of battery cell, and head compression assembly includes the upper pressure head and lower pressure head being located on the upper and lower sides of the head position of battery cell and the second cylinder being located in the upper of upper pressure head, and upper pressure head and lower pressure head carry out compression operation to the head position of battery cell.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery technology, and in particular to a short-circuit test structure for lithium-ion batteries. Background Technology

[0002] After welding, pouch cells require short-circuit testing. To ensure accuracy, the positive and negative electrodes and separator must be tightly bonded. If the separator is damaged, the positive and negative electrodes will contact each other, forming a conductive circuit, indicating a defect and the cell will be rejected. Short-circuit testing typically uses an upper and lower pressure plate and a test probe. The upper and lower pressure plates compact the cell, and the test probe connects to the battery's tabs. Because the cell is formed by stacking positive and negative electrodes and a separator, due to cell design, the negative electrode tail area is covered by positive electrode tab aluminum foil. There is a thickness difference between the positive electrode tab area and the aluminum foil, meaning there is a gap between the negative electrode, separator, and positive electrode aluminum foil at the beginning of the cell. During the normal pressing process, this gap cannot be compacted, creating a risk of undetectable short circuits at this location. This could lead to defective products entering the market and posing a safety hazard. Utility Model Content

[0003] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a short-circuit test structure for lithium-ion batteries.

[0004] The objective of this utility model is achieved through the following technical solution:

[0005] A short-circuit test structure for a lithium-ion battery includes: a worktable, a battery cell placed on the worktable, a main pressing assembly and a head pressing assembly for pressing different parts of the battery cell. The main pressing assembly is used to press the middle region of the battery cell. The main pressing assembly includes a pressure plate disposed above the battery cell and a first cylinder located on the pressure plate. The first cylinder is used to drive the pressure plate downward to press the middle region of the battery cell. There are two head pressing assemblies, which are used to press two head positions of the battery cell. The head pressing assembly includes an upper pressing head and a lower pressing head disposed on the upper and lower sides of the head position of the battery cell, and a second cylinder disposed above the upper pressing head. The upper pressing head and the lower pressing head perform pressing operations corresponding to the head positions of the battery cell.

[0006] In one embodiment, the size of the workbench is smaller than the size of the battery cell, the middle region of the battery cell is placed on the workbench, and the two head positions of the battery cell are located outside the workbench area.

[0007] In one embodiment, the thickness at the two head positions of the battery cell is less than the thickness of the middle region of the battery cell.

[0008] In one embodiment, the pressure plate has a plurality of pressure strips on the side facing the battery cell. The plurality of pressure strips are arranged along the length direction of the pressure plate and are equidistantly distributed along the width direction of the pressure plate.

[0009] In one embodiment, the worktable is provided with a plurality of protrusions, the plurality of protrusions protruding from the surface of the worktable, the plurality of protrusions being staggered from the plurality of pressure strips, the plurality of protrusions being arranged along the width direction of the worktable, and the plurality of protrusions being equidistantly distributed along the length direction of the worktable.

[0010] In one embodiment, a rubber layer is provided on the side of the plurality of pressure strips facing the battery cell and on the side of the plurality of protrusions facing the battery cell.

[0011] In one embodiment, the upper pressure head has a first inclined surface on the side facing the battery cell. The first inclined surface is inclined upward from the side away from the main pressing assembly to the side closer to the main pressing assembly. The height difference between the highest point and the lowest point of the first inclined surface is 1.5 mm.

[0012] In one embodiment, the pressing head has a second inclined surface on the side facing the battery cell. The second inclined surface is inclined downward from the side away from the main pressing assembly to the side closer to the main pressing assembly. The height difference between the highest point and the lowest point of the second inclined surface is 1 mm.

[0013] In one embodiment, the first inclined surface of the upper pressure head and the second inclined surface of the lower pressure head are arranged opposite to each other, and the horizontal length of the first inclined surface of the upper pressure head is 9.8 mm, the horizontal length of the second inclined surface of the lower pressure head is 10 mm, and the lowest point of the first inclined surface and the highest point of the second inclined surface are aligned and pressed together at the head edge of the battery cell.

[0014] In one embodiment, the upper pressure head has a positioning part on its side. The positioning part is vertically arranged and located on the side of the upper pressure head away from the main pressing assembly. The lower end face of the positioning part is lower than the lowest point of the first inclined surface of the upper pressure head, and the height difference between the lower end face of the positioning part and the lowest point of the first inclined surface is 1.5mm.

[0015] Compared with the prior art, the present invention has at least the following advantages:

[0016] 1. The lithium-ion battery short-circuit test structure of this utility model improves the situation where the head of the battery cell is not compacted during the pressing process by setting a head pressing component at the head position of the battery cell. When pressing the battery cell, the main pressing component presses the middle area of ​​the battery cell, and the two head pressing components press the two head positions of the battery cell respectively. The pressing surfaces of the upper and lower pressing heads in the two head pressing components are inclined surfaces, so that the internal gap of the battery cell is squeezed and compacted, thereby increasing the probability of short circuit detection at the head position of the battery cell and preventing defective products from entering the market.

[0017] 2. The lithium-ion battery short-circuit test structure of this utility model has a positioning part set on the side of the upper pressure head. When the upper pressure head and the lower pressure head are aligned and pressed to the head position of the battery cell, the positioning part is located outside the battery cell. The positioning part is used to position the upper pressure head and the lower pressure head so that when they are aligned, the positioning part abuts against the outside of the lower pressure head, so as to ensure that the upper pressure head and the lower pressure head press the head position of the battery cell. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the embodiments will be briefly described below.

[0019] Figure 1 This is a schematic diagram of a short-circuit test structure for a lithium-ion battery provided by this utility model;

[0020] Figure 2 A schematic diagram of the pressure bar on the pressure plate in a short-circuit test structure for a lithium-ion battery provided by this utility model;

[0021] Figure 3 This is a schematic diagram of the protrusions on the worktable in a short-circuit test structure for a lithium-ion battery provided by this utility model.

[0022] Figure descriptions: 10. Workbench; 11. Protrusion; 20. Battery cell; 30. Main pressing assembly; 31. Pressure plate; 311. Pressure strip; 32. First cylinder; 40. Head pressing assembly; 41. Upper pressure head; 411. First inclined surface; 412. Positioning part; 42. Lower pressure head; 421. Second inclined surface; 43. Second cylinder. Detailed Implementation

[0023] To facilitate understanding of this utility model, a more comprehensive description of this utility model will be given below with reference to the accompanying drawings.

[0024] A short-circuit test structure for lithium-ion batteries, referring to Figure 1The system includes a worktable 10, a battery cell 20 placed on the worktable 10, a main pressing assembly 30 for pressing different parts of the battery cell 20, and a head pressing assembly 40. The main pressing assembly 30 is used to press the middle area of ​​the battery cell 20. There are two head pressing assemblies 40, located on either side of the main pressing assembly 30, and used to press the two head positions of the battery cell 20. It should be noted that the size of the worktable 10 is smaller than the size of the battery cell 20. The middle area of ​​the battery cell 20 is placed on the worktable 10, while the two head positions of the battery cell 20 are located outside the worktable 10.

[0025] Reference Figure 1 The thickness of the two head positions of the battery cell 20 is less than the thickness of the middle region of the battery cell 20. By setting two head pressing assemblies 40 to press the two head positions of the battery cell 20 separately, the tightness between the positive electrode plate, negative electrode plate and separator inside the head position of the battery cell 20 is ensured, thereby increasing the probability of short circuit detection. It should be noted that there is a certain distance between the main pressing assembly 30 and the two head pressing assemblies 40 to avoid mutual interference.

[0026] Reference Figure 1 The main pressing assembly 30 includes a pressure plate 31 located above the middle area of ​​the battery cell 20 and a first cylinder 32 located on the pressure plate 31. The first cylinder 32 is used to drive the pressure plate 31 downward to cooperate with the worktable 10 to perform a pressing operation on the middle area of ​​the battery cell 20.

[0027] Reference Figure 1 and Figure 2 The pressure plate 31 is arranged in a plane. Multiple pressure strips 311 are provided on the side of the pressure plate 31 facing the cell 20. The multiple pressure strips 311 are arranged along the length direction of the pressure plate 31 and are equally distributed along the width direction of the pressure plate 31. The multiple pressure strips 311 are used to increase the pressure inside the cell 20 when pressing it, so as to improve the tightness between the positive electrode, the negative electrode and the separator.

[0028] Furthermore, referring to Figure 1 and Figure 3 The worktable 10 is provided with a plurality of protrusions 11, which protrude from the surface of the worktable 10. The plurality of protrusions 11 and the plurality of pressure strips 311 are staggered. The plurality of protrusions 11 are arranged along the width direction of the worktable 10 and are equidistantly distributed along the length direction of the worktable 10. When the first cylinder 32 controls the pressure plate 31 to press down, the plurality of pressure strips 311 on the pressure plate 31 and the plurality of protrusions 11 on the worktable 10 increase the pressure on the battery cell 20, so that when the upper and lower force-bearing surfaces of the battery cell 20 are squeezed, the positive electrode, negative electrode and separator inside the battery cell 20 can be tightly attached.

[0029] In one embodiment, multiple pressure strips 311 are arranged along the width direction of the pressure plate 31, and the multiple pressure strips 311 are evenly distributed along the length direction of the pressure plate 31. The multiple pressure strips 311 are linearly distributed to change the surface force of the pressure plate 31 on the middle area of ​​the battery cell 20 into a linear force, thereby increasing the pressure when pressing the battery cell 20, improving the tightness of each layer inside the battery cell 20, and ensuring the reliability of the battery cell 20 test results.

[0030] Furthermore, a rubber layer is provided on the side of the multiple pressure strips 311 facing the battery cell 20 and on the side of the multiple protrusions 11 facing the battery cell 20. The rubber layer is used to abut against the battery cell 20 to reduce the wear caused to the battery cell 20 by direct contact between the pressure strips 311 or protrusions 11 and the battery cell 20.

[0031] Furthermore, both the pressure strip 311 and the protrusion 11 are made of insulating material. The pressure strip 311 and the protrusion 11 made of insulating material can prevent the pressure plate 31 and the worktable 10 from affecting the short-circuit test results of the battery cell 20 after they are pressed together.

[0032] Furthermore, referring to Figure 1 The head pressing assembly 40 includes an upper pressing head 41 and a lower pressing head 42 located on the upper and lower sides of the head position of the battery cell 20, and a second cylinder 43 disposed above the upper pressing head 41. The upper pressing head 41 and the lower pressing head 42 are arranged opposite to each other, and the head position of the battery cell 20 is located between the upper pressing head 41 and the lower pressing head 42. The upper pressing head 41 and the lower pressing head 42 perform pressing operations corresponding to the head position of the battery cell 20. Both the upper pressing head 41 and the lower pressing head 42 are inclined. The upper pressing head 41 has a first inclined surface 411 on the side facing the battery cell 20. The first inclined surface 411 is inclined upward from the side away from the main pressing assembly 30 toward the side closer to the main pressing assembly 30.

[0033] In one implementation, reference Figure 1 The height difference between the highest and lowest points of the first inclined surface 411 is 1.5 mm. The height difference between the highest and lowest points of the first inclined surface 411 is determined by the thickness of the battery cell 20.

[0034] Furthermore, referring to Figure 1 The pressure head 42 has a second inclined surface 421 on the side facing the cell 20. The second inclined surface 421 is inclined downward from the side away from the main pressing assembly 30 toward the side close to the main pressing assembly 30.

[0035] In one implementation, reference Figure 1 The height difference between the highest and lowest points of the second inclined surface 421 is 1 mm. The height difference between the highest and lowest points of the second inclined surface 421 is determined by the thickness of the battery cell 20.

[0036] Reference Figure 1 The first inclined surface 411 of the upper pressure head 41 and the second inclined surface 421 of the lower pressure head 42 are arranged opposite to each other, and the horizontal length of the first inclined surface 411 of the upper pressure head 41 is 9.8 mm, and the horizontal length of the second inclined surface 421 of the lower pressure head 42 is 10 mm. When the upper pressure head 41 and the lower pressure head 42 are pressing the head position of the battery cell 20, the second cylinder 43 controls the upper pressure head 41 to descend, so that the lowest point of the first inclined surface 411 of the upper pressure head 41 and the highest point of the second inclined surface 421 of the lower pressure head 42 jointly press the head edge of the battery cell 20, so that the internal gaps of the battery cell 20 are compressed and compacted, and the force at the head position of the battery cell 20 extends to the middle area of ​​the battery cell 20, so as to ensure that each layer of the battery cell 20 can be completely compacted. It should be noted that by creating high pressure at the lowest point of the first inclined surface 411 of the upper pressure head 41 and the highest point of the second inclined surface 421 of the lower pressure head 42 where there are many gaps at the head of the battery cell 20, high pressure is formed to compact the gaps at the head of the battery cell 20, thereby ensuring the reliability of the battery cell 20 test results.

[0037] Furthermore, referring to Figure 1 The upper pressure head 41 has a positioning part 412 on its side. The positioning part 412 is vertically arranged and located on the side of the upper pressure head 41 away from the main pressing assembly 30. The lower end surface of the positioning part 412 is lower than the lowest point of the first inclined surface 411 of the upper pressure head 41. The height difference between the lower end surface of the positioning part 412 and the lowest point of the first inclined surface 411 is 1.5mm. The positioning part 412 has a width of 5.2 mm and a length longer than the upper pressure head 41. That is, the positioning part 412 extends out of the first inclined surface 411 of the upper pressure head 41. When the upper pressure head 41 and the lower pressure head 42 are aligned and pressed to the head position of the battery cell 20, the positioning part 412 is located outside the battery cell 20. The positioning part 412 is used to position the battery cell 20 so that when the upper pressure head 41 and the lower pressure head 42 are aligned, the positioning part 412 abuts against the outside of the lower pressure head 42 to ensure that the upper pressure head 41 and the lower pressure head 42 perform the pressing operation on the head position of the battery cell 20.

[0038] This invention improves the situation where the head of the battery cell 20 is not compacted during pressing by setting a head pressing component 40 at the head position of the battery cell 20. When pressing the battery cell 20, the main pressing component 30 presses the middle area of ​​the battery cell 20, and the two head pressing components 40 press the two head positions of the battery cell 20 respectively. The pressing surfaces of the upper pressing head 41 and the lower pressing head 42 in the two head pressing components 40 are inclined surfaces, so that the internal gap of the battery cell 20 is squeezed and compacted, thereby increasing the probability of short circuit detection at the head position of the battery cell 20 and preventing defective products from entering the market.

[0039] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A short-circuit test structure for a lithium-ion battery, characterized in that, include: The workbench (10), the battery cell (20) placed on the workbench (10), the main pressing assembly (30) for pressing different parts of the battery cell (20) and the head pressing assembly (40), the main pressing assembly (30) for pressing the middle area of ​​the battery cell (20), the main pressing assembly (30) includes a pressure plate (31) disposed above the battery cell (20) and a first cylinder (32) located on the pressure plate (31), the first cylinder (32) for driving the pressure plate (31) downwards to press the battery cell. (20) is pressed in the middle area; there are two head pressing components (40), which are used to press the two head positions of the battery cell (20). The head pressing components (40) include an upper pressing head (41) and a lower pressing head (42) located on the upper and lower sides of the head position of the battery cell (20) and a second cylinder (43) located above the upper pressing head (41). The upper pressing head (41) and the lower pressing head (42) perform pressing operations corresponding to the head positions of the battery cell (20).

2. The short-circuit test structure for a lithium-ion battery according to claim 1, characterized in that, The size of the workbench (10) is smaller than the size of the battery cell (20). The middle area of ​​the battery cell (20) is placed on the workbench (10), and the two head positions of the battery cell (20) are located outside the range of the workbench (10).

3. The lithium-ion battery short-circuit test structure according to claim 1, characterized in that, The thickness of the two head positions of the battery cell (20) is less than the thickness of the middle region of the battery cell (20).

4. The short-circuit test structure for a lithium-ion battery according to claim 1, characterized in that, The pressure plate (31) has a plurality of pressure strips (311) on the side facing the battery cell (20). The plurality of pressure strips (311) are arranged along the length direction of the pressure plate (31) and are equidistantly distributed along the width direction of the pressure plate (31).

5. A short-circuit test structure for a lithium-ion battery according to claim 4, characterized in that, The workbench (10) is provided with a plurality of protrusions (11), which protrude from the surface of the workbench (10). The plurality of protrusions (11) are staggered from the plurality of pressure strips (311). The plurality of protrusions (11) are arranged along the width direction of the workbench (10) and are equidistantly distributed along the length direction of the workbench (10).

6. The short-circuit test structure for a lithium-ion battery according to claim 5, characterized in that, A rubber layer is provided on the side of the plurality of pressure strips (311) facing the battery cell (20) and on the side of the plurality of protrusions (11) facing the battery cell (20).

7. The short-circuit test structure for a lithium-ion battery according to claim 1, characterized in that, The upper pressure head (41) has a first inclined surface (411) on the side facing the battery cell (20). The first inclined surface (411) is inclined upward from the side away from the main pressing assembly (30) towards the side close to the main pressing assembly (30). The height difference between the highest point and the lowest point of the first inclined surface (411) is 1.5mm.

8. A short-circuit test structure for a lithium-ion battery according to claim 7, characterized in that, The pressing head (42) has a second inclined surface (421) on the side facing the battery cell (20). The second inclined surface (421) is inclined downward from the side away from the main pressing assembly (30) towards the side close to the main pressing assembly (30). The height difference between the highest point and the lowest point of the second inclined surface (421) is 1 mm.

9. A short-circuit test structure for a lithium-ion battery according to claim 8, characterized in that, The first inclined surface (411) of the upper pressure head (41) and the second inclined surface (421) of the lower pressure head (42) are arranged opposite to each other. The horizontal length of the first inclined surface (411) of the upper pressure head (41) is 9.8 mm, and the horizontal length of the second inclined surface (421) of the lower pressure head (42) is 10 mm. The lowest point of the first inclined surface (411) and the highest point of the second inclined surface (421) are aligned and pressed together at the head edge of the battery cell (20).

10. A short-circuit test structure for a lithium-ion battery according to claim 9, characterized in that, The upper pressure head (41) has a positioning part (412) on its side. The positioning part (412) is vertically arranged and located on the side of the upper pressure head (41) away from the main pressing assembly (30). The lower end face of the positioning part (412) is lower than the lowest point of the first inclined surface (411) of the upper pressure head (41). The height difference between the lower end face of the positioning part (412) and the lowest point of the first inclined surface (411) is 1.5mm.

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