Center needle structure of cylindrical lithium ion battery

Abstract

The utility model discloses a central needle structure of a cylindrical lithium ion battery, which comprises a central needle body, the central needle body is of a hollow tubular structure, a spiral winding strip is wound on the circumference of the central needle body, and the winding strip comprises a protruding part protruding outwards. The spiral winding strip is arranged, the winding strip comprises the protruding part protruding outwards, the protruding part abuts against the inner wall of the center hole of the roll core, so that the center needle body is completely attached to the inner wall of the roll core, and the problem that in the circulation process, the roll core deforms towards the inner layer close to the gap of the center hole, and collapse is caused is solved; the winding strip is made of a heat-conducting silica gel material and has good heat conductivity and elasticity, on one hand, heat in the winding core can be rapidly conducted to the outside in time when the battery core generates heat, the safety performance of the battery core is effectively improved, and on the other hand, the winding strip can play a buffering role when the battery core is impacted by a heavy object, and the risk that the inner ring of the battery core is damaged is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of lithium ion batteries, and particularly relates to a central pin structure of a cylindrical lithium ion battery. Background Art

[0002] Lithium-ion batteries currently have the advantages of high energy, long service life, low self-discharge rate, light weight, and green environmental protection. They are widely used in mobile phones, laptops, power tools, electric vehicles, street lights, backup power supplies, navigation lights and small household appliances.

[0003] The battery cell in a cylindrical lithium-ion battery is formed by winding the positive and negative electrodes and the separator into a cylindrical shape. A central pin is inserted into the interior of the battery cell to support the outer winding core and prevent it from collapsing and deforming.

[0004] However, the existing center needle cannot completely fit into the center hole of the winding core, thereby being unable to completely avoid potential safety hazards. Utility Model Content

[0005] The purpose of the present invention is to provide a center pin structure for a cylindrical lithium-ion battery to solve the problems mentioned in the background art. The present invention provides a center pin structure for a cylindrical lithium-ion battery that can completely fit the center pin to the inner wall of the winding core.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a center needle structure of a cylindrical lithium-ion battery, comprising a center needle body, the center needle body being a hollow tubular structure, a spiral winding strip wound around the circumference of the center needle body, the winding strip including a protruding portion protruding outward.

[0007] In order to provide a positioning and fixing surface for the winding strip, a spiral groove corresponding to the winding strip is further provided on the circumference of the center needle body.

[0008] Furthermore, the surface of the raised portion is an arc-shaped or planar structure.

[0009] In order to quickly transfer the heat inside the winding core to the outside when the battery cell generates heat, improve the safety performance of the battery cell, and act as a buffer when the battery cell is hit by heavy objects, thereby reducing the risk of damage to the inner ring of the battery cell, the winding strip is further made of thermal conductive silicone.

[0010] In order to reduce the degree of depression of the center hole of the battery cell during the cycle, an auxiliary layer whose thickness increases after absorbing the electrolyte is further attached to the surface of the raised part. The auxiliary layer is a water-based polyurethane polymer material. The porosity of the auxiliary layer is 40% to 80%, the average pore diameter is 5μm-50μm, and the thickness is 45-80um.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1. The utility model provides a spiral winding strip on the outside of the center needle body. The winding strip includes an outwardly protruding protrusion. The protrusion abuts against the inner wall of the center hole of the winding core, so that the center needle body and the inner wall of the winding core are completely in contact, thus preventing the winding core from deforming toward the inner layer near the center hole during the circulation process and causing collapse.

[0013] 2. The center needle body of the present invention is provided with a spiral groove on its circumference corresponding to the winding strip, which is used to provide a positioning and fixing surface for the winding strip;

[0014] 3. The wrapping strip of this utility model is made of thermally conductive silicone material, which has good thermal conductivity and elasticity. On the one hand, when the battery core generates heat, it can quickly transfer the heat inside the winding core to the outside, effectively improving the safety performance of the battery core. On the other hand, it can act as a buffer when the battery core is hit by heavy objects, reducing the risk of damage to the inner ring of the battery core.

[0015] 4. The surface of the raised portion of the utility model is attached with an auxiliary layer whose thickness increases after absorbing electrolyte. The auxiliary layer is a water-based polyurethane polymer material. The auxiliary layer of the water-based polyurethane polymer material has a high porosity and can absorb electrolyte. After absorbing the electrolyte, the auxiliary layer increases in thickness and cooperates with the winding strip to fill the gap between the center needle body and the winding core, so that the center needle body and the center hole of the winding core fit more closely, reducing the degree of depression of the center hole of the battery cell during the cycle. At the same time, it can store more electrolyte, which can timely replenish the electrolyte consumption of the battery cell during the cycle, ensuring the electrolyte required for long cycles;

[0016] 5. The auxiliary layer of the waterborne polyurethane polymer material of the utility model has good elasticity and can cooperate with the winding strip to play a buffering role when the battery core is impacted by external force, further improving the safety of the battery core;

[0017] 6. The auxiliary layer of the water-based polyurethane polymer material of the utility model absorbs a small amount of water to form a film with certain physical and mechanical properties. Its surface is smooth, which can avoid damaging the inner core when inserted into the center hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural diagram of the utility model;

[0019] Figure 2 This is a schematic structural diagram of the center needle body of the utility model;

[0020] Figure 3 This is a schematic structural diagram of another embodiment of the present utility model;

[0021] In the figure: 1. Center needle body; 2. Winding strip; 3. Auxiliary layer; 4. Spiral groove. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1

[0024] See also Figure 1-2 The utility model provides the following technical solutions: a center needle structure of a cylindrical lithium-ion battery, comprising a center needle body 1, the center needle body 1 being a hollow tubular structure, a spiral winding strip 2 being wound around the circumference of the center needle body 1, and the winding strip 2 including a protruding portion protruding outward.

[0025] By adopting the above-mentioned technical solution, the utility model provides a spiral winding strip 2 on the outside of the center needle body 1. The winding strip 2 includes a protruding portion protruding outward, which abuts against the inner wall of the center hole of the winding core through the protruding portion, so that the center needle body 1 is completely fitted with the inner wall of the winding core, avoiding the problem of the winding core deforming toward the inner layer close to the center hole gap during the circulation process and causing collapse.

[0026] Specifically, a spiral groove 4 corresponding to the winding strip 2 is provided on the circumference of the central needle body 1 .

[0027] By adopting the above technical solution, a positioning and fixing surface is provided for the winding strip 2 .

[0028] Specifically, the surface of the raised portion is an arc-shaped structure.

[0029] Specifically, the wrapping strip 2 is made of thermally conductive silicone material.

[0030] By adopting the above technical solution, it has good thermal conductivity and elasticity. On the one hand, when the battery cell generates heat, the heat inside the winding core can be quickly transferred to the outside in time, effectively improving the safety performance of the battery cell. On the other hand, it can play a buffering role when the battery cell is hit by a heavy object, reducing the risk of damage to the inner ring of the battery cell.

[0031] Example 2

[0032] See also Figure 3 The difference between this embodiment and embodiment 1 is that: specifically, the surface of the raised portion is a planar structure.

[0033] Example 3

[0034] The difference between this embodiment and embodiment 1 is that: specifically, an auxiliary layer 3 whose thickness increases after absorbing the electrolyte is attached to the surface of the raised portion, the auxiliary layer 3 is a water-based polyurethane polymer material, the porosity of the auxiliary layer 3 is 40% to 80%, the average pore size is 5μm-50μm, and the thickness is 45-80um.

[0035] By adopting the above technical solution, the auxiliary layer 3 of the water-based polyurethane polymer material has a high porosity and can absorb electrolyte. After absorbing the electrolyte, its thickness increases, and it cooperates with the winding strip 2 to fill the gap between the center needle body 1 and the core, so that the center needle body 1 fits more closely with the center hole of the core, reducing the degree of depression of the center hole of the battery cell during the cycle, and at the same time can store more electrolyte, and can replenish the electrolyte consumption of the battery cell during the cycle in time, ensuring the electrolyte required for long cycle; the auxiliary layer 3 of the water-based polyurethane polymer material has good elasticity, and can cooperate with the winding strip 2 to play a buffering role when the battery cell is impacted by external force, thereby further improving the safety of the battery cell; the auxiliary layer 3 of the water-based polyurethane polymer material absorbs a small amount of water to form a thin film with certain physical and mechanical properties, and its surface is smooth, which can avoid damage to the inner core when inserted into the center hole.

[0036] Example 4

[0037] The difference between this embodiment and embodiment 1 is that: specifically, the total thickness of the protrusion and the auxiliary layer 3 is slightly smaller than the gap between the center needle body 1 and the center hole of the winding core. In this embodiment, for the winding core with an inner diameter of the center hole of 3.5-3.8 mm and an outer diameter of the center needle body 1 of 3.0 mm, the total thickness of the protrusion and the auxiliary layer 3 is 0.4-0.7 mm, and the protrusion refers to the part protruding from the outer wall of the center needle body 1.

[0038] By adopting the above technical solution, the assembly of the center needle body and the winding core is facilitated.

[0039] In summary, the present invention provides a spiral winding strip 2 on the outside of the center needle body 1, and the winding strip 2 includes a protruding portion protruding outward, which abuts against the inner wall of the center hole of the winding core through the protruding portion, so that the center needle body 1 is completely fitted with the inner wall of the winding core, thereby avoiding the problem of the winding core deforming toward the inner layer close to the center hole gap during the cycle and causing collapse; a spiral groove 4 corresponding to the winding strip 2 is provided on the circumference of the center needle body 1 of the present invention, which is used to provide a positioning and fixing surface for the winding strip 2; the winding strip 2 of the present invention is made of thermal conductive silicone material, which has good thermal conductivity and elasticity. On the one hand, when the battery core generates heat, it can quickly and promptly conduct the heat inside the winding core to the outside, effectively improving the safety performance of the battery core; on the other hand, it can play a buffering role when the battery core is hit by a heavy object, reducing the risk of damage to the inner ring of the battery core; an auxiliary layer 3 with an increased thickness after absorbing electrolyte is attached to the surface of the protruding portion of the utility model The auxiliary layer 3 is a water-based polyurethane polymer material. The auxiliary layer 3 of the water-based polyurethane polymer material has a high porosity and can absorb electrolyte. After absorbing the electrolyte, its thickness increases, and it cooperates with the winding strip 2 to fill the gap between the center needle body 1 and the core, so that the center needle body 1 fits more closely with the center hole of the core, reducing the degree of depression of the center hole of the battery cell during the cycle, and at the same time can store more electrolyte, and can replenish the electrolyte consumption of the battery cell during the cycle in time, ensuring the electrolyte required for long cycle; the auxiliary layer 3 of the water-based polyurethane polymer material of the utility model has good elasticity, and can cooperate with the winding strip 2 to play a buffering role when the battery cell is impacted by external force, thereby further improving the safety of the battery cell; the auxiliary layer 3 of the water-based polyurethane polymer material of the utility model absorbs a small amount of water to form a film with certain physical and mechanical properties, and its surface is smooth, which can avoid damage to the inner core when inserted into the center hole.

[0040] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A center pin structure for a cylindrical lithium-ion battery, comprising a center pin body, characterized in that: A spiral winding strip is wound around the circumference of the central needle body, and the winding strip includes a protruding portion protruding outward.

2. The center pin structure of a cylindrical lithium-ion battery according to claim 1, characterized in that: The central needle body is a hollow tubular structure.

3. The center pin structure of a cylindrical lithium-ion battery according to claim 1, characterized in that: The circumference of the central needle body is provided with a spiral groove corresponding to the winding strip.

4. The center pin structure of a cylindrical lithium-ion battery according to claim 1, characterized in that: The surface of the raised portion is an arc-shaped or plane-shaped structure.

5. The center pin structure of a cylindrical lithium-ion battery according to claim 1, characterized in that: The winding strip is made of thermally conductive silicone material.

6. The center pin structure of a cylindrical lithium-ion battery according to claim 1, characterized in that: An auxiliary layer whose thickness increases after absorbing electrolyte is attached to the surface of the protrusion.

7. The center pin structure of a cylindrical lithium-ion battery according to claim 6, characterized in that: The auxiliary layer is made of waterborne polyurethane polymer material.

8. The center pin structure of a cylindrical lithium-ion battery according to claim 7, characterized in that: The auxiliary layer has a porosity of 40% to 80%, an average pore diameter of 5 μm to 50 μm, and a thickness of 45 to 80 μm.

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