Soft package battery cell liquid supplementing structure

Abstract

The utility model provides a soft package battery cell liquid supplementing structure which comprises a battery cell body, the battery cell body comprises a battery cell formed by winding or stacking a positive pole piece, a diaphragm and a negative pole piece, a positive pole lug arranged on the positive pole piece, a negative pole lug arranged on the negative pole piece and an aluminum plastic film wrapping the battery cell, the battery cell is sealed by the top end of the aluminum plastic film through a seal; a liquid supplementing opening is formed in the upper end of the seal and is positioned between the positive pole lug and the negative pole lug; according to the utility model, the electrolyte supplementing port is reserved at the sealing edge of the tab of the soft package battery cell, and when the electrolyte of the battery cell is less or is quickly dried up, the electrolyte can be injected into the battery cell through the electrolyte supplementing port at the sealing edge of the tab, so that on one hand, the electrolyte of the battery can be supplemented, the internal resistance of the battery is reduced, and the cycle life is prolonged; on the other hand, the pole piece can be infiltrated again, some dry active substances are activated, and the capacity is improved.

Description

Technical Field

[0001] The utility model relates to the field of lithium-ion batteries, in particular to a soft-pack battery core liquid replenishing structure. Background Art

[0002] The soft-pack battery cell includes an aluminum-plastic film and a laminate encapsulated in the aluminum-plastic film. The laminate includes a plurality of pole pieces stacked in sequence and a diaphragm that electronically isolates adjacent pole pieces.

[0003] During the battery pack's EOL (End of Life) phase and during use, the electrolyte within the soft-pack cells will be depleted, causing capacity decay. This depletion of electrolyte often leads to low capacity, increased internal resistance, and reduced cycle life. Simply categorizing batteries based on capacity and internal resistance will significantly reduce their value and shorten their lifespan. Soft-pack cells are difficult to open after heat-sealing, making it impossible to refill the electrolyte, impacting their performance and service life.

[0004] To this end, we propose a soft-pack battery cell refilling structure to solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to solve the shortcomings of the prior art. In order to achieve the above purpose, this utility model adopts the following technical solutions:

[0006] A soft-pack battery cell refill structure comprises a battery cell body, wherein the battery cell body is formed by winding or stacking a positive electrode sheet, a separator and a negative electrode sheet, a positive electrode tab provided on the positive electrode sheet, a negative electrode tab provided on the negative electrode sheet, and an aluminum-plastic film wrapped around the battery cell, wherein the top end of the aluminum-plastic film seals the battery cell by a seal; a refill port is provided at the upper end of the seal, and the refill port is located between the positive electrode tab and the negative electrode tab.

[0007] Further preferably, the seal includes an aluminum-plastic film sealing area and a top sealing area, the aluminum-plastic film sealing area is located directly below the fluid infusion port, the top sealing area is located on both sides of the aluminum-plastic film sealing area, and the tearing force of the aluminum-plastic film sealing area is smaller than the tearing force of the top sealing area.

[0008] Further preferably, the liquid infusion port is enclosed by an aluminum-plastic film sealing area and a top sealing area to form a frame-shaped structure with an open top.

[0009] Further preferably, the aluminum-plastic film sealing area is a ladder-shaped structure, and the size of the aluminum-plastic film sealing area close to the battery cell end is smaller than the size away from the battery cell end.

[0010] Further preferably, the sum of the length of the liquid replenishing port and the width of the sealing areas on both sides is smaller than the gap between the positive electrode tab and the negative electrode tab.

[0011] Further preferably, the width of the liquid replenishing port is smaller than the thickness of the battery cell body.

[0012] Compared with the prior art, the beneficial effects of the present invention are:

[0013] The utility model reserves a liquid replenishing port at the edge sealing of the pole ear of the soft-pack battery cell. When the electrolyte in the battery cell is low or is about to dry up, the electrolyte replenishing port at the edge sealing of the pole ear can be used to inject electrolyte into the battery cell. On the one hand, the electrolyte of the battery can be replenished, thereby reducing the internal resistance of the battery and increasing the cycle life. On the other hand, the pole piece can be re-infiltrated to activate some dried active substances and increase the capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the utility model;

[0015] Figure 2 This is the main view of the utility model;

[0016] Figure 3 It is a side sectional view of the present utility model.

[0017] In the figure: battery cell body 1, aluminum-plastic film 2, positive electrode tab 3, liquid filling port 4, aluminum-plastic film sealing area 5, negative electrode tab 6, top sealing area 7. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0019] Reference Figure 1-Figure 3 A soft-pack battery cell refilling structure includes a battery cell body 1, wherein the battery cell body 1 is a battery cell formed by winding or stacking a positive electrode sheet, a separator and a negative electrode sheet, a positive electrode tab 3 arranged on the positive electrode sheet, a negative electrode tab 6 arranged on the negative electrode sheet, and an aluminum-plastic film 2 wrapped around the battery cell, and the top of the aluminum-plastic film 2 seals the battery cell by sealing; the sealing is completed by hot pressing, ultrasonic welding, structural adhesive bonding, etc.; a refilling port 4 is provided at the upper end of the seal, and the refilling port 4 is located between the positive electrode tab 3 and the negative electrode tab 6.

[0020] The utility model reserves a liquid replenishing port 4 at the edge sealing of the pole ear of the soft-pack battery cell. When the electrolyte in the battery cell is low or is about to dry up, the electrolyte replenishing port 4 at the edge sealing of the pole ear can be used to inject electrolyte into the battery cell. On the one hand, the electrolyte of the battery can be replenished, thereby reducing the internal resistance of the battery and increasing the cycle life. On the other hand, the pole piece can be re-infiltrated to activate some dried active substances and increase the capacity.

[0021] In the embodiment, the hot pressing adopts upper and lower die heads to press the aluminum-plastic film, and the upper and lower die heads need to be heated, the heating temperature is (170-210) ° C, and the hot pressing time is (2-6) s.

[0022] The seal includes an aluminum-plastic film sealing area 5 and a top sealing area 7. The aluminum-plastic film sealing area 5 is located directly below the fluid infusion port 4, and the top sealing area 7 is located on both sides of the aluminum-plastic film sealing area 5. The tearing force of the aluminum-plastic film sealing area 5 is smaller than the tearing force of the top sealing area 7.

[0023] In the embodiment: a liquid filling port 4 is reserved at the edge of the tab of the soft-pack battery cell. The flow channel of the liquid filling port 4 is made of PP, PE and other electrolyte corrosion-resistant materials. The hot compressive strength of the liquid filling port flow channel is lower than that of the aluminum-plastic film. The flow channel will not be damaged during normal use of the battery cell and can be opened by external force in the later stage. The hot compressive strength requirements of the aluminum-plastic film sealing area 5 below the liquid filling port are: tearing force <1.5N / mm; the hot compressive strength of the top sealing area 7 must be >2.5N / mm. Due to the cycle of the battery cell, the electrolyte is continuously consumed and may dry up gradually. After the electrolyte is reduced or dried up, The electrolyte flow channel can be opened physically (but not limited to physical means). Then, using a liquid injection device, the injection nozzle is connected to the liquid filling port 4, and electrolyte is injected to soak the electrode. After the electrolyte is injected, the aluminum-plastic film of the liquid filling port 4 can be resealed by hot pressing, ultrasonic welding, structural adhesive bonding, etc. Once the electrolyte is replenished, the lithium ion transport medium is replenished in a timely manner, and the active lithium content in the battery is further replenished, thereby improving the cycle performance. By re-filling the retired soft-pack power battery, the retired battery is provided with an appropriate amount of electrolyte. On the one hand, the battery electrolyte is replenished, thereby reducing the battery internal resistance and increasing the cycle life. On the other hand, it can re-wet the electrode, activate some dried active materials, and increase the capacity.

[0024] In the embodiment: Physical method: Use a non-metallic cutting device such as a ceramic blade to cut the glue on the edge of the liquid injection port to allow the inner cavity of the battery cell to leak out.

[0025] Other forms: Use a solvent to coat the glue opening in the heat-sealing area to dissolve the heat-sealing glue, allowing the inner cavity of the battery cell to leak out.

[0026] The liquid inlet 4 is enclosed by the aluminum-plastic film sealing area 5 and the top sealing area 7 to form a frame structure with an open top.

[0027] In the embodiment, the liquid inlet 4 is a frame-shaped structure with three sides (bottom and side) sealed by aluminum-plastic films 2 on both sides and an open top.

[0028] The aluminum-plastic film sealing area 5 is a ladder-shaped structure. The size of the aluminum-plastic film sealing area 5 close to the battery cell end is smaller than the size away from the battery cell end.

[0029] In the embodiment, the upper end of the aluminum-plastic film sealing area 5 is consistent with the size of the liquid filling port 4, and the lower end of the aluminum-plastic film sealing area 5 is smaller than the upper end, so that the aluminum-plastic film sealing area 5 has a ladder-shaped structure. The liquid filling port 4 will not be damaged during normal use of the battery cell, and the liquid filling port 4 can be opened by external force in the later stage.

[0030] The sum of the length of the liquid filling port 4 and the width of the sealing areas on both sides is smaller than the gap between the positive electrode tab 3 and the negative electrode tab 6 ; the width of the liquid filling port 4 is smaller than the thickness of the battery cell body 1 .

[0031] In the embodiment, the liquid filling port 4 is located between the positive electrode tab 3 and the negative electrode tab 6 , and the width of the liquid filling port 4 is smaller than the thickness of the battery cell body 1 .

[0032] The utility model reserves a liquid replenishing port at the edge sealing of the pole ear of the soft-pack battery cell. When the electrolyte in the battery cell is low or is about to dry up, the electrolyte replenishing port at the edge sealing of the pole ear can be used to inject electrolyte into the battery cell. On the one hand, the electrolyte of the battery can be replenished, thereby reducing the internal resistance of the battery and increasing the cycle life. On the other hand, the pole piece can be re-infiltrated to activate some dried active substances and increase the capacity.

Claims

1. A soft-pack battery cell refilling structure, characterized in that: The battery cell body comprises a battery cell formed by winding or stacking a positive electrode sheet, a separator and a negative electrode sheet, a positive electrode tab arranged on the positive electrode sheet, a negative electrode tab arranged on the negative electrode sheet and an aluminum-plastic film wrapped around the battery cell, wherein the top end of the aluminum-plastic film seals the battery cell by a seal; a liquid filling port is provided at the upper end of the seal, and the liquid filling port is located between the positive electrode tab and the negative electrode tab.

2. The soft-pack battery cell refilling structure according to claim 1, characterized in that: The seal includes an aluminum-plastic film sealing area and a top sealing area. The aluminum-plastic film sealing area is located directly below the fluid infusion port, and the top sealing area is located on both sides of the aluminum-plastic film sealing area. The tearing force of the aluminum-plastic film sealing area is smaller than the tearing force of the top sealing area.

3. The soft-pack battery cell refilling structure according to claim 2, characterized in that: The liquid infusion port is enclosed by an aluminum-plastic film sealing area and a top sealing area to form a frame structure with an open top.

4. The soft-pack battery cell refilling structure according to claim 2, characterized in that: The aluminum-plastic film sealing area is a ladder-shaped structure, and the size of the aluminum-plastic film sealing area close to the battery cell end is smaller than the size away from the battery cell end.

5. The soft-pack battery cell refilling structure according to claim 1, characterized in that: The sum of the length of the liquid replenishing port and the width of the sealing areas on both sides is smaller than the gap between the positive electrode tab and the negative electrode tab.

6. The soft-pack battery cell refilling structure according to claim 1, characterized in that: The width of the liquid replenishing port is smaller than the thickness of the battery cell body.

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