Button cell

Abstract

The application provides a button cell, comprising a negative electrode shell, a positive electrode shell and an internal component, the negative electrode shell and the positive electrode shell form a cavity, the internal component is located in the cavity, the direction from the negative electrode shell to the positive electrode shell is defined as a first direction, along the first direction, the internal component comprises a spring, a first gasket, a negative electrode sheet, a separation film, a positive electrode sheet and a second gasket which are sequentially stacked, wherein along the first direction, the maximum size of the cavity is a first size, the size of the internal component is a second size, and the ratio of the second size to the first size is 82% to 83.6%. The application places the gasket and limits the ratio of the thickness of the internal component in the button cell to the overall internal thickness of the button cell, so that the contact between the components in the button cell is close, thereby improving the conductivity and consistency of the button cell.

Description

Technical Field

[0001] This application relates to the field of button cell technology, and specifically to a button cell. Background Technology

[0002] Lithium-ion button batteries are widely used in the verification and evaluation of various materials for lithium-ion batteries due to their advantages such as convenient assembly, small size, low cost and short verification cycle.

[0003] However, existing coin cells have poor contact between the electrodes and other components, and the consistency of mass-produced coin cells is also poor, resulting in low data accuracy during material verification and evaluation. Utility Model Content

[0004] In view of this, in order to solve at least one of the above technical problems, this application provides a button cell battery.

[0005] This application provides a button cell battery, including: a negative electrode shell, a positive electrode shell, and an internal component. The negative electrode shell and the positive electrode shell form a cavity, and the internal component is located within the cavity. A first direction is defined as the direction from the negative electrode shell to the positive electrode shell. Along the first direction, the internal component includes a spring sheet, a first gasket, a negative electrode sheet, a separator, a positive electrode sheet, and a second gasket, which are stacked sequentially. The maximum size of the cavity along the first direction is a first size, and the size of the internal component is a second size. The second size accounts for 82% to 83.6% of the first size.

[0006] In some possible embodiments, the second dimension accounts for 82.5% to 83.5% of the first dimension.

[0007] In some possible embodiments, the first pad includes a first surface and a second surface disposed opposite to each other, the roughness of the first surface being greater than the roughness of the second surface, the first surface abutting against the spring sheet, and the second surface abutting against the negative electrode sheet.

[0008] In some possible embodiments, the second gasket includes a third surface and a fourth surface disposed opposite to each other, the roughness of the third surface being greater than the roughness of the fourth surface, the third surface abutting against the positive electrode shell, and the fourth surface abutting against the positive electrode sheet.

[0009] In some possible embodiments, the negative electrode comprises at least one of graphite and silicon-carbon composite materials.

[0010] In some possible embodiments, an electrolyte is provided between any two adjacent elements of the first pad, the negative electrode, the separator, and the positive electrode.

[0011] In some possible embodiments, the mass of the electrolyte between the first pad and the negative electrode is less than the mass of the electrolyte between the negative electrode and the separator, and the mass of the electrolyte between the first pad and the negative electrode is less than the mass of the electrolyte between the positive electrode and the separator.

[0012] In some possible embodiments, the projection of the negative electrode on the first pad is located inside the first pad in a direction opposite to the first direction; and the projection of the positive electrode on the second pad is located inside the second pad in the first direction.

[0013] In some possible embodiments, the projection of the negative electrode on the separator is located inside the separator in a direction opposite to the first direction; and the projection of the positive electrode on the separator is located inside the separator in the first direction.

[0014] In some possible embodiments, the coin cell is a lithium-ion coin cell full cell.

[0015] Compared to existing technologies, the coin cell provided in this application provides a method that places pads on both sides of the positive electrode, separator, and negative electrode (cell structure) and limits the ratio of the thickness of the internal components (second dimension) to the overall thickness of the coin cell (first dimension) to a suitable range. This ensures close contact between the components in the coin cell, improves the contact between the positive and negative electrode sheets and the separator, thereby enhancing the conductivity and assembly consistency of the coin cell. This allows the coin cell to better and faster evaluate the performance of the positive or negative electrode material. Attached Figure Description

[0016] Figure 1 This is an exploded view of the overall structure of a button battery provided in an embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the overall structure of a button battery provided in an embodiment of this application.

[0018] Figure 3 A planar sectional view provided for an embodiment of this application.

[0019] Figure 4 This is a partial exploded view of the structure of a button battery provided in an embodiment of this application.

[0020] Figure 5 This is an exploded view of the overall structure of a button cell provided in another embodiment of this application.

[0021] The attached figures are labeled as follows: 100 for button cell, 1 for negative electrode shell, 2 for spring sheet, 3 for first pad, 4 for negative electrode sheet, 5 for separator, 6 for positive electrode sheet, 7 for second pad, 8 for positive electrode shell, 9 for electrolyte, 10 for internal components, 20 for cavity, 30 for cell structure, 301 for first surface, 302 for second surface, 701 for third surface, and 702 for fourth surface. Detailed Implementation

[0022] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0023] It should be noted that when a component is referred to as "connected to," "fixed to," or "mounted to" another component, it can be directly on the other component or may have an intervening component. When a component is considered to be "set on" another component, it can be directly set on the other component or may have an intervening component. The term "and / or" as used herein includes all and any combination of one or more of the related listed items.

[0024] Please see Figures 1 to 5 As shown, this application embodiment provides a coin cell battery 100, including: a negative electrode shell 1, a positive electrode shell 8, and an internal component 10. The negative electrode shell 1 and the positive electrode shell 8 form a cavity 20, and the internal component 10 is located within the cavity 20. The direction from the negative electrode shell 1 to the positive electrode shell 8 is defined as a first direction Z. Along the first direction Z, the internal component 10 includes a spring sheet 2, a first gasket 3, a negative electrode sheet 4, a separator 5, a positive electrode sheet 6, and a second gasket 7 stacked sequentially. The maximum size of the cavity 20 along the first direction Z is a first size, and the size of the internal component 10 is a second size, with the second size accounting for 82% to 83.6% of the first size. Specifically, the coin cell battery 100 can be a lithium-ion coin cell full battery, but is not limited thereto.

[0025] In the button cell 100, the spring 2 provides pressure to make the internal components come into close contact, and the first gasket 3 and the second gasket 7 can evenly transfer this pressure and other externally applied pressure to the abutting positive electrode 6 and negative electrode 4, which is beneficial to the contact between the electrode plates (positive electrode 6 and negative electrode 4) and the separator 5.

[0026] This application specifies that the thickness (second dimension) of the internal component 10 in the coin cell 100 is in the range of 82% to 83.6% of the height (first dimension) of the overall internal cavity 20 of the coin cell 100. This allows for closer contact between the components in the coin cell 100, improves the contact between the positive electrode 6 and the negative electrode 4 and the separator 5, reduces interface resistance, and facilitates efficient lithium-ion conduction. This, in turn, enhances the conductivity and assembly consistency of the coin cell 100, enabling faster and more efficient evaluation of the performance of the positive or negative electrode materials. Furthermore, since the positive electrode 6 or the negative electrode 4 is prone to volume changes during cycling, a second dimension within the aforementioned range provides a buffer for these volume changes, reducing the risk of the separator 5 rupture due to expansion and compression, and improving the safety of the coin cell 100.

[0027] The positive electrode, separator, and negative electrode constitute the cell structure 30. When the proportion of the second dimension to the first dimension is too low (less than 82%), the internal components are difficult to fit tightly together, resulting in microscopic unevenness within the cell structure 30. This leads to point or line contacts rather than ideal surface contacts, making it difficult for lithium ions and electrons to transport at poorly contacted interfaces, thus increasing the internal resistance of the coin cell 100. When the proportion of the second dimension to the first dimension is too high (greater than 83.6%), it causes excessive compression of the cell structure 30, leading to electrode material breakage. This is especially true for brittle electrode materials such as graphite and silicon-carbon composites, where excessive compression is more likely to cause electrode breakage. Furthermore, excessive compression of the cell structure 30 can also break the separator 5, causing an internal short circuit. Therefore, controlling the proportion of the second dimension to the first dimension within the range of 82% to 83.6% can effectively improve the interface contact inside the cell structure 30, achieve good surface contact, and prevent the electrode sheets from being crushed. This improves the conductivity and safety of the coin cell 100. At the same time, limiting the size of the internal component 30 within the above range can also improve the consistency of the coin cell 100 manufacturing process and improve the data accuracy when verifying and evaluating materials for the coin cell 100.

[0028] Based on the above advantages, the coin cell 100 provided in this application embodiment is particularly suitable for cases where the negative electrode 4 is made of graphite or silicon-carbon composite material. Graphite or silicon-carbon composite material itself has poor flexibility, making it difficult to form a tight face-to-face contact with the separator 5, and instead easily forming point or line contacts, leading to a decrease in the conductivity of the coin cell 100. Furthermore, the thinness of the graphite negative electrode further reduces the contact between the graphite negative electrode and the separator 5. Applying graphite or silicon-carbon composite material to the coin cell 100 provided in this application embodiment, by clearly defining the ratio of the second dimension to the first dimension, can effectively solve the above-mentioned problems. This coin cell 100 has a wide range of applicability, which is beneficial for large-scale applications. In addition, compared to lithium metal sheets as the negative electrode 4, graphite and silicon-carbon composite materials as the negative electrode 4 can reduce the deposition of lithium dendrites, reducing the risk of lithium dendrites piercing the separator 5 and causing a short circuit in the coin cell 100, thereby further improving the safety of the coin cell 100.

[0029] The proportion of the second dimension to the first dimension can, for example, be 82%, 82.1%, 82.2%, 82.3%, 82.4%, 82.5%, 82.6%, 82.7%, 82.8%, 82.9%, 83%, 83.1%, 83.2%, 83.3%, 83.4%, 83.5%, 83.6%, or any value within the range of any two of the above values.

[0030] Furthermore, the proportion of the second dimension to the first dimension can be 82.5% to 83.5%, which is beneficial to further balance the interfacial contact between the electrode materials (positive electrode 6 and negative electrode 4) and the separator 5 in the button cell 100 and the overall safety of the button cell 100.

[0031] Please see Figure 4 As shown, the first pad 3 includes a first surface 301 and a second surface 302 disposed opposite to each other. The roughness of the first surface 301 is greater than that of the second surface 302. The first surface 301 abuts against the spring 2, and the second surface 302 abuts against the negative electrode 4. The placement direction of the first pad 3 is specified so that the smoother second surface 302 of the first pad 3 contacts the negative electrode 4. On the one hand, this further improves the tightness of the interface contact, and on the other hand, it can reduce the risk of short circuit in the button cell 100 caused by damage to the separator 5 (the separator 5 and the negative electrode 4 are located on the same side of the first pad 3) caused by the rough first surface 301, thereby improving the safety of the button cell 100 and the consistency of the button cell 100 assembly.

[0032] Please see Figure 4As shown, the second gasket 7 includes a third surface 701 and a fourth surface 702 disposed opposite to each other. The roughness of the third surface 701 is greater than that of the fourth surface 702. The third surface 701 abuts against the positive electrode shell 8, and the fourth surface 702 abuts against the positive electrode sheet 6. The placement direction of the second gasket 7 is specified so that the smoother fourth surface 702 of the second gasket 7 contacts the positive electrode sheet 6. On the one hand, this further improves the tightness of the interface contact, and on the other hand, it can reduce the risk of short circuit in the coin cell 100 caused by damage to the separator 5 (the separator 5 and the positive electrode sheet 6 are located on the same side of the second gasket 7) caused by the rough third surface 701, thereby improving the safety of the coin cell 100 and the consistency of the coin cell 100 assembly.

[0033] In some embodiments, both the first and second gaskets are made of stainless steel, which can provide stable support.

[0034] Please see Figure 5 As shown, electrolyte 9 can be provided between any two adjacent elements of the first pad 3, negative electrode 4, separator 5, and positive electrode 6. Adding electrolyte 9 at the above-mentioned positions helps the electrolyte 9 to wet the positive electrode 6, negative electrode 4, and separator 5, forming a continuous ion conduction path and an electron conduction path.

[0035] Furthermore, the mass of the electrolyte 9 between the first gasket 3 and the negative electrode 4 is less than the mass of the electrolyte 9 between the negative electrode 4 and the separator 5, and the mass of the electrolyte 9 between the first gasket 3 and the negative electrode 4 is less than the mass of the electrolyte 9 between the positive electrode 6 and the separator 5. This is because the material of the first gasket 3 does not easily adsorb the electrolyte 9, and reducing the amount of electrolyte 9 added helps to reduce the risk of corrosion of the positive electrode shell 8 and the negative electrode shell 1.

[0036] Specifically, the button cell 100 can be obtained through the following assembly steps: Step 1: First place the negative electrode shell 1; Step 2: Place the spring piece 2 on the negative electrode shell 1; Step 3: Place the first gasket 3 on the spring piece 2, with the first surface 301 of the first gasket 3 abutting against the spring piece 2. Step 4: Add approximately 20 μl of electrolyte 9 to the second surface 302 of the first gasket 3; Step 5: Place the negative electrode 4 on the second surface 302 of the first pad 3, with the second surface 302 abutting against the negative electrode 4, and the electrolyte 9 wets the negative electrode. Step 6: Add approximately 50 μl of electrolyte 9 to the negative electrode 4; Step 7: Place the separator 5 on the negative electrode plate 4, and wet the separator 5 with electrolyte 9; Step 8: Add approximately 50 μl of electrolyte solution to the separator membrane. Step 9: Place the positive electrode 6 on the separator 5, and wet the positive electrode 6 with electrolyte 9; Step 10: Place the second pad 7 on the positive electrode 6, with the fourth surface 702 of the second pad 7 abutting against the positive electrode 6. Step 11: Place the positive electrode shell 9 on the third surface 701 of the second pad 7; Step 12: Fasten the negative electrode shell 1 and the positive electrode shell 8 together.

[0037] Please see Figure 1 Along the direction opposite to the first direction Z, the projection of the negative electrode 4 on the first pad 3 is located inside the first pad 3, which helps the first pad 3 to flatten the negative electrode 4 and provides comprehensive protection and fixation for the negative electrode 4.

[0038] Along the first direction Z, the projection of the positive electrode 6 onto the second pad 7 is located inside the second pad 7, which helps the second pad 7 to flatten the positive electrode 6 and provides comprehensive protection and fixation for the positive electrode 6.

[0039] Along the direction opposite to the first direction Z, the projection of the negative electrode 4 onto the separator 5 is located inside the separator 5; and along the first direction Z, the projection of the positive electrode 6 onto the separator 5 is located inside the separator 5, which is beneficial to completely isolate the positive electrode 6 and the negative electrode 4, and avoid the positive electrode 6 and the negative electrode 7 from contacting each other, which would cause the button cell 100 to short circuit.

[0040] Compared to existing technologies, the coin cell 100 provided in this application embodiment places a second pad 7 and a first pad 3 on both sides of the positive electrode 6-separator 5-negative electrode 4 (cell structure 30), and limits the ratio of the thickness (second dimension) of the internal component 10 in the coin cell 100 to the height (first dimension) of the internal cavity 20 in the coin cell 100 to a suitable range. This makes the contact between the components in the coin cell 100 tight, improves the interfacial contact between the positive electrode 6 and negative electrode 4 and the separator 5, and forms a good surface contact, thereby improving the conductivity of the coin cell 100. It also provides a clear standard for the ratio of the second dimension to the first dimension, thereby improving the consistency of the coin cell 100 assembly, so that the coin cell 100 can better and faster evaluate the performance of the positive electrode material or the negative electrode material.

[0041] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this application, and this application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this application, and these modifications and improvements are also considered to be within the scope of protection of this application.

Claims

1. A button cell battery, characterized in that, include: The device comprises a negative electrode shell, a positive electrode shell, and an internal component. The negative electrode shell and the positive electrode shell form a cavity. The internal component is located within the cavity. A first direction is defined as the direction from the negative electrode shell to the positive electrode shell. Along the first direction, the internal component includes a spring sheet, a first gasket, a negative electrode sheet, a separator, a positive electrode sheet, and a second gasket, which are stacked sequentially. The maximum size of the cavity along the first direction is a first size, and the size of the internal component is a second size. The second size accounts for 82% to 83.6% of the first size.

2. The button cell battery as described in claim 1, characterized in that, The second dimension accounts for 82.5% to 83.5% of the first dimension.

3. The button cell battery as described in claim 1, characterized in that, The first pad includes a first surface and a second surface disposed opposite to each other, the roughness of the first surface is greater than the roughness of the second surface, the first surface abuts against the spring sheet, and the second surface abuts against the negative electrode sheet.

4. The button cell battery as described in claim 1, characterized in that, The second gasket includes a third surface and a fourth surface disposed opposite to each other, the roughness of the third surface being greater than the roughness of the fourth surface, the third surface abutting against the positive electrode shell, and the fourth surface abutting against the positive electrode sheet.

5. The button cell battery as described in claim 1, characterized in that, The negative electrode includes at least one of graphite and silicon-carbon composite materials.

6. The button cell battery as described in claim 1, characterized in that, An electrolyte is provided between any two adjacent elements of the first gasket, the negative electrode, the separator, and the positive electrode.

7. The button cell battery as described in claim 6, characterized in that, The mass of the electrolyte between the first pad and the negative electrode is less than the mass of the electrolyte between the negative electrode and the separator, and the mass of the electrolyte between the first pad and the negative electrode is less than the mass of the electrolyte between the positive electrode and the separator.

8. The button cell battery as described in claim 1, characterized in that, Along a direction opposite to the first direction, the projection of the negative electrode sheet onto the first pad is located inside the first pad; Along the first direction, the projection of the positive electrode sheet onto the second pad is located inside the second pad.

9. The button cell battery as described in claim 8, characterized in that, Along a direction opposite to the first direction, the projection of the negative electrode on the separator is located inside the separator; and along the first direction, the projection of the positive electrode on the separator is located inside the separator.

10. The button cell battery as described in claim 1, characterized in that, The coin cell is a lithium-ion coin cell.

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