Liquid supplementing structure in later liquid storage period of soft package battery cell

Abstract

The utility model provides a liquid supplementing structure in the later liquid storage period of a soft package battery cell. A 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 two opposite sides of the aluminum plastic film in the width direction seal the battery cell through a top sealing area, a plurality of electrolyte sealing bags are arranged at the top sealing area, and electrolyte is sealed in the electrolyte sealing bags; according to the utility model, the electrolyte sealing bag is arranged at the sealing edge of the tab of the soft package battery cell, a part of electrolyte is stored in the electrolyte sealing bag, and the electrolyte in the electrolyte sealing bag is squeezed into the battery cell when the electrolyte of the battery cell is less or is quickly dried up, so that on one hand, the electrolyte of the battery can be supplemented; 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 liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage. Background Art

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

[0003] In the EOL (End of Life) stage of the battery pack and during use, the electrolyte inside the soft-pack battery cell will be consumed, resulting in the attenuation of the capacity of the soft-pack battery cell. A large part of the battery cell has a low capacity, an increased internal resistance, and a reduced cycle life due to the consumption of the electrolyte. If it is simply classified and utilized according to the capacity and internal resistance, the utilization value of the power battery will be greatly reduced, and the secondary utilization life of the battery will be reduced. Moreover, it is difficult to open the soft-pack battery cell after hot-pressing the edge sealing, and the electrolyte cannot be replenished, which affects the performance and service life of the battery cell.

[0004] Therefore, we propose a liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage to solve the above problems. Content of the Utility Model

[0005] The purpose of the utility model is to solve the disadvantages existing in the prior art. To achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage includes a battery cell body. The battery cell body is composed of a battery cell formed by winding or stacking a positive pole piece, a separator, and a negative pole piece, a positive pole tab arranged on the positive pole piece, a negative pole tab arranged on the negative pole piece, and an aluminum-plastic film wrapped around the battery cell. The positive pole tab and the negative pole tab are respectively located on opposite sides of the battery cell in the width direction. The aluminum-plastic film seals the battery cell through top-sealing areas on opposite sides in the width direction. Several electrolyte storage packages are arranged at the top-sealing areas, and the electrolyte storage packages are hermetically sealed with electrolyte.

[0007] Further preferably, the liquid storage amount of the electrolyte storage package is 10% - 20% of the initial liquid injection amount of the battery cell.

[0008] Further preferably, a thermally sealed virtual welding area is arranged on the side of the electrolyte storage package adjacent to the battery cell, and the tearing force of the thermally sealed virtual welding area is less than the tearing force of the top-sealing area.

[0009] Further preferably, the height of the electrolyte storage package does not exceed the surface of the battery cell.

[0010] Further preferably, the number of the electrolyte storage packages is 4, and the 4 electrolyte storage packages are located in the top-sealing area.

[0011] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0012] The present utility model provides an electrolyte storage package at the ear edge sealing of a soft-pack battery cell. By storing a part of the electrolyte in the electrolyte storage package, when the electrolyte in the battery cell is less or nearly dried up, the electrolyte inside the electrolyte storage package is squeezed into the battery cell. On the one hand, the electrolyte of the battery can be supplemented, thereby reducing the internal resistance of the battery and increasing the cycle life. On the other hand, the electrode plate can be wetted again to activate some dried active substances and improve the capacity. Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of the present utility model;

[0014] Figure 2 is a front view of the present utility model;

[0015] Figure 3 is a side sectional view of the present utility model.

[0016] In the figure: battery cell body 1, aluminum-plastic film 2, positive electrode ear 3, electrolyte storage package 4, negative electrode ear 5, heat-sealing virtual soldering area 6, top-sealing area 7. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments.

[0018] Referring to Figures 1 - 3 , a liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage, including a battery cell body 1, the battery cell body 1 is composed of a battery cell formed by winding or stacking a positive electrode plate, a separator and a negative electrode plate, a positive electrode ear 3 arranged on the positive electrode plate, a negative electrode ear 5 arranged on the negative electrode plate, and an aluminum-plastic film 2 wrapped around the battery cell. The positive electrode ear 3 and the negative electrode ear 5 are respectively located on opposite sides of the battery cell in the width direction. The aluminum-plastic film 2 seals the battery cell through top-sealing areas 7 on opposite sides in the width direction. Several electrolyte storage packages 4 are arranged at the top-sealing areas 7, and the electrolyte storage packages 4 are hermetically sealed with electrolyte.

[0019] The present utility model provides an electrolyte storage package 4 at the ear edge sealing of a soft-pack battery cell. By storing a part of the electrolyte in the electrolyte storage package 4, when the electrolyte in the battery cell is less or nearly dried up, the electrolyte inside the electrolyte storage package 4 is squeezed into the battery cell to wet the electrode plate, activate some dried active substances, and improve the capacity.

[0020] In the embodiment: The top sealing area 7 is sealed by hot pressing. For hot pressing, the upper and lower die heads are used to press the aluminum-plastic film tightly, and the upper and lower die heads need to be heat-treated. The heating temperature is (170 - 210) °C, and the hot pressing time is (2 - 6) s.

[0021] The liquid storage capacity of the electrolyte storage package 4 is 10% - 20% of the initial liquid injection volume of the battery cell.

[0022] In the embodiment: By controlling the liquid storage capacity of the electrolyte storage package 4, not only can the electrolyte of the battery be fully replenished, but also the size of the electrolyte storage package 4 can be appropriately controlled.

[0023] A heat-sealed virtual welding area 6 is arranged on one side of the electrolyte storage package 4 adjacent to the battery cell, and the tearing force of the heat-sealed virtual welding area 6 is less than the tearing force of the top sealing area 7.

[0024] In the embodiment: An electrolyte storage package 4 is arranged at the edge of the tab of the soft-pack battery cell. The electrolyte storage package 4 is made of materials resistant to electrolyte corrosion such as PP and PE. A heat-sealed virtual welding area 6 is arranged on one side of the electrolyte storage package 4 adjacent to the battery cell. The tearing force of the heat-sealed virtual welding area 6 is less than the tearing force of the top sealing area 7, that is, the hot pressing strength of the heat-sealed virtual welding area 6 is lower than that of the top sealing area 7. The heat-sealed virtual welding area 6 can be opened by an external force later.

[0025] Requirements for the hot pressing strength of the heat-sealed virtual welding area 6: Tearing force < 0.3 N / mm; Requirements for the hot pressing strength of the top sealing area 7: > 2.5 N / mm; Due to the cycling of the battery cell, the electrolyte may be continuously consumed and gradually dry out. After the electrolyte decreases or dries out, the heat-sealed virtual welding area 6 can be opened by a physical method (clamping plate extrusion, destroying the heat-sealed virtual welding area) later, and the normal seal on the outside will not be damaged, and the electrolyte in the electrolyte storage package 4 is released into the battery cell to infiltrate the electrode plate; after replenishing the electrolyte, the lithium-ion transmission medium is timely replenished, and the active lithium content in the battery is further replenished, and the cycling performance is improved. By re-supplying liquid to the retired soft-pack power battery, an appropriate amount of electrolyte can be obtained for the retired battery. On the one hand, the electrolyte of the battery can be replenished, thereby reducing the internal resistance of the battery and increasing the cycling life. On the other hand, the electrode plate can be infiltrated again to activate some dried active substances and improve the capacity.

[0026] The height of the electrolyte storage package 4 does not exceed the surface of the battery cell; the number of the electrolyte storage packages 4 is 4, and the 4 electrolyte storage packages 4 are located in the top sealing area 7.

[0027] In the embodiment: The electrolyte storage packages 4 are located at the four corners of the battery cell. The electrolyte storage packages 4 at the four corners can evenly supply electrolyte to the battery cell, so that all the electrode plates of the battery cell can be infiltrated, avoiding the drying out of local active substances due to the lack of electrolyte, thereby reducing the internal resistance of the battery and increasing the cycling life.

[0028] The utility model provides an electrolyte storage package at the edge sealing of the tab of a soft-pack battery cell. A part of electrolyte is stored in the electrolyte storage package. When the electrolyte in the battery cell is less or nearly dried up, the electrolyte inside the electrolyte storage package is squeezed into the battery cell. On the one hand, the electrolyte of the battery can be supplemented, thereby reducing the internal resistance of the battery and increasing the cycle life. On the other hand, the electrode plate can be infiltrated again to activate some dried-up active substances and improve the capacity.

Claims

1. A liquid replenishment structure for a soft-pack battery cell in the later stage of liquid storage, characterized in that, It includes a battery cell body, the battery cell body is composed of a battery cell formed by winding or stacking a positive electrode tab, a separator and a negative electrode tab, a positive electrode tab disposed on the positive electrode tab, a negative electrode tab disposed on the negative electrode tab, and an aluminum-plastic film wrapped around the battery cell. The positive electrode tab and the negative electrode tab are respectively located on opposite sides of the battery cell in the width direction. The aluminum-plastic film seals the battery cell through a top-sealing area on opposite sides in the width direction. Several electrolyte storage packages are provided at the top-sealing area, and the electrolyte storage packages are hermetically sealed with electrolyte.

2. The liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage according to claim 1, wherein, The liquid storage capacity of the electrolyte storage package is 10% - 20% of the initial liquid injection volume of the battery cell.

3. The liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage according to claim 1, characterized in that, A heat-sealing virtual soldering area is provided on one side of the electrolyte storage package adjacent to the battery cell, and the tearing force of the heat-sealing virtual soldering area is less than the tearing force of the top-sealing area.

4. A liquid replenishment structure for a soft-pack battery cell in the later stage of liquid storage, characterized in that, The height of the electrolyte storage package does not exceed the surface of the battery cell.

5. The liquid replenishing structure for a soft-pack battery cell in the later stage of liquid storage according to claim 1, wherein, The number of the electrolyte storage packages is 4, and the 4 electrolyte storage packages are located within the top-sealing area.

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