CN203288661U - Cylindrical steel shell lithium ion battery - Google Patents

Abstract

The utility model relates to the technical field of lithium-ion batteries, in particular to a cylindrical steel-cased lithium-ion battery, comprising a battery steel case, a battery core housed in the battery steel case and an electrolyte filled therein, and the surface of the battery core is uniformly coated with The soft polymer material layer adopts this technical solution to fix the battery core well, so that the battery core can effectively inhibit the expansion of the anode during the actual cycle process, thereby maintaining a good electrochemical interface. At the same time, it can absorb the vibration energy of the battery during use, which is beneficial to alleviate the hidden dangers of short circuit and tab twisting caused by shaking inside the battery core during actual transportation and vibration. Moreover, the soft polymer material layer can reduce the pressure and damage of the rigidity and hardness of the steel shell to the battery core.

Description

A cylindrical steel case lithium-ion battery

technical field

The utility model relates to the technical field of lithium ion batteries, in particular to a cylindrical steel shell lithium ion battery.

Background technique

As a green and environmentally friendly battery, lithium-ion batteries have the advantages of high energy density, high operating voltage and long service life, and are widely used in mobile power tools. Cylindrical lithium-ion batteries generally include a battery case, a battery core accommodated in the battery case and an electrolyte filled therein, and the battery core includes a cathode pole piece, an anode pole piece and a separator.

Lithium-ion batteries for power tools have a wide market, and they have their own special characteristics, requiring large discharge current and high power performance. At the same time, the actual use environment of electric tools is relatively harsh. After the battery core is charged and discharged at high temperature and at a high rate, the cathode and anode sheets will expand due to structural changes, and the active material in the electrode sheet is easy to peel off, resulting in insufficient battery core interface. good. In the actual use of power tools, the vibration intensity is high, and the mechanical mechanics and reliability requirements of the battery core are very high. Therefore, lithium-ion batteries for power tools often use steel shells with high rigidity and mechanical strength as the battery core shell. However, during actual transportation or use, the steel shell with high rigidity and strength will exert different degrees of pressure and damage on the battery core. Moreover, lithium-ion batteries for power tools that seek to increase power density do not require high energy density, so the battery core is usually relatively small, and the specifications of the steel shell are fixed, such as 18650, 26650, etc., then the battery core in the steel shell Experience the shaking up and down, left and right, resulting in the potential short circuit of the battery core or the pole piece due to the shaking inside the battery cell during transportation.

To sum up, it is indeed necessary to provide a battery core structure that can not only ensure the mechanical strength, but also absorb the vibration energy of the battery during transportation and use and maintain a superior interface during the cycle process, so as to comply with the development of lithium-ion batteries for electric tools. demand.

Utility model content

The purpose of the utility model is to overcome the deficiencies of the prior art, and provide a device that can not only ensure the mechanical strength, but also absorb the vibration energy of the battery core during transportation and use, and can also be used during the charging and discharging cycle of the battery core. , keep the interface nice.

In order to solve the above-mentioned technical problems, the cylindrical battery provided by the utility model includes a battery steel case, a battery core contained in the battery steel case and an electrolyte filled therein, and the surface of the battery core is uniformly coated with a soft polymer material layer. The soft polymer material layer itself is easy to be compressed, which can reduce the pressure and damage of the rigidity of the steel case to the battery core. The soft polymer material can absorb the energy of the battery during use and vibration, which can help alleviate the hidden dangers of the battery core during transportation and vibration, and solve the hidden danger of short circuit caused by shaking inside the battery core. The material of the soft polymer material layer can be polymer glue such as styrene-butadiene rubber, polyvinylidene fluoride, α-cyanoacrylate, etc., and the material is required to have high temperature resistance, impact resistance, vibration resistance, softness, etc. characteristics, and the soft polymer material layer is an electronic insulating layer. the

The thickness of the soft polymer material layer is 0.5-5.0mm. The thickness of the soft polymer material layer can be adjusted according to the actual ratio of the battery core volume to the internal volume of the steel case, so as to ensure that the battery core can be inserted into the steel case smoothly. Such surface treatment of the battery core, due to the good elasticity of the soft polymer material layer, improves the expansion and contraction capacity of the battery core, and effectively inhibits the expansion of the cathode and anode during high-temperature, high-rate cycles, thereby maintaining a good battery life. The chemical interface improves the battery cycle performance.

The soft polymer material layer is one or more layers.

The soft polymer material layer is an electronic insulating layer.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the battery core of the present invention.

Fig. 2 is a schematic diagram of a battery core structure coated with a uniform soft polymer material layer in the present invention.

Fig. 3 is a top view of a battery core structure coated with a uniform soft polymer material layer in the present invention.

Figure 4 is a cross-sectional view of the utility model steel case lithium-ion battery.

Detailed ways

In order to make the purpose, technical solution and advantages of the present utility model clearer, it will be further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

As shown in Figure 1, the current output terminal 2 is welded on the empty metal foil surface of the cathode and anode by winding, and then the cathode, anode and separator with the tabs welded are wound into a bare battery core 1.

As shown in Figure 2, a soft polymer material layer 3 is uniformly painted on the surface of the bare battery core 1, and the thickness of the soft polymer material layer 3 can be adjusted according to the actual energy density of the battery and the diameter of the battery core 1. The object material layer 3 can be one or more layers, and the thickness is 0.5-5.0mm. In order to ensure that the battery core 1 is inserted into the steel case 4 smoothly, the gap space between the battery core 1 and the steel case 4 is as small as possible.

See Fig. 3, considering the practical purpose of the soft polymer material layer 3, the material of the soft polymer material layer 3 can be polymer glues such as styrene-butadiene rubber, polyvinylidene fluoride, α-cyanoacrylate, etc., select The material requirements have the characteristics of high temperature resistance, high strength, impact resistance, vibration resistance, softness and so on.

As shown in FIG. 4 , the battery core 1 that has been wound and coated with the soft polymer material layer 3 is put into the steel shell 4 by manual or machine means. The subsequent cathode and anode lugs are welded to the corresponding positive and negative electrodes, and the electrolyte solution is injected into the steel shell 4. After vacuuming and sealing, the desired cylindrical lithium ion battery can be obtained.

The utility model paints a certain thickness of the soft polymer material layer 3 to occupy the empty space between the battery core and the steel shell 4, and fixes the battery core 1 well, effectively inhibiting the expansion of the cathode and anode, thereby maintaining a good electrochemical interface all the time. . At the same time, it can absorb the vibration energy of the battery during use, and avoid tab breakage or other possible short circuit hazards caused by shaking of the battery core 1 during transportation and actual vibration use. Reduce the pressure and damage of the rigidity of the steel shell 4 on the battery core, and improve the safety of the battery.

According to the disclosure of the above specification, those skilled in the art to which the present utility model belongs can also make appropriate changes and modifications to the above embodiment. Therefore, the utility model is not limited to the specific implementation manners disclosed and described above, and some modifications and changes to the utility model should also fall within the scope of protection of the claims of the utility model. In addition, although some specific terms are used in this utility model, these terms are only for convenience of description and do not limit the utility model patent in any way.

Claims (4)

1. a cylinder type steel case lithium ion battery, comprise battery steel shell, is contained in battery and the electrolyte that is filled in wherein in battery steel shell, and it is characterized in that: the battery surface uniform is coated with and is brushed with the soft polymeric material layer.

2. a kind of cylinder type steel case lithium ion battery as claimed in claim 1, it is characterized in that: the thickness of described soft polymeric material layer is 0.5-5.0mm.

3. a kind of cylinder type steel case lithium ion battery as claimed in claim 2, it is characterized in that: described soft polymeric material layer is one deck or multilayer.

4. a kind of cylinder type steel case lithium ion battery as claimed in claim 3, it is characterized in that: described soft polymeric material layer is the electronic isolation layer.

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