Split type elastic enhanced low internal resistance conductive structure for cylindrical lithium battery

Abstract

The application discloses a split type elastic reinforced low internal resistance conductive structure for cylindrical lithium batteries, which comprises a conductive part 1, an elastic part 2, a blackening prevention contact surface 3, a supporting and positioning structure 4 and a mounting clamp 5. The conductive part 1 is made of high-conductive material and is used for bearing current conduction; the elastic part 2 is used for providing elastic pressure and preventing poor contact caused by deformation, and is independent of the conductive part 1 and does not participate in current conduction; the supporting and positioning structure 4 and the mounting clamp 5 are used for fixing the conductive part 1 and the elastic part 2 assembly in the battery cabin. The structure has the advantages of low contact resistance, high current carrying capacity, strong blackening resistance, long service life and adaptability to various types of cylindrical lithium batteries.

Description

Technical Field

[0001] This invention relates to the field of battery connection structure technology, and in particular to a low internal resistance spring sheet structure with separate elastic force and conductive path suitable for various sizes of cylindrical lithium batteries. Background Technology

[0002] The positive and negative terminals of cylindrical lithium batteries are typically electrically connected by spot welding copper-nickel sheets or springs of different structures. Traditional structures mainly include monolithic manganese steel springs and integral stamped copper springs. Monolithic manganese steel springs are low in cost, but have poor conductivity and high internal resistance. In high-current scenarios, their end faces are prone to blackening or oxidation, affecting battery life and safety.

[0003] Although integrally stamped copper sheets or copper springs have good electrical conductivity, they have poor elasticity and are prone to permanent deformation after repeated insertion and removal or being squeezed, resulting in insufficient contact pressure and problems such as poor contact and increased contact resistance.

[0004] Existing contact springs generally adopt an integrated design of elasticity and conductive path. The loss of elasticity will directly lead to a decrease in conductivity, making it difficult to meet the performance requirements of "high elasticity" and "low internal resistance". In addition, this type of structure is usually non-removable and non-maintainable, and is difficult to replace or repair after long-term use.

[0005] In applications with currents of 10A to 30A or even higher, traditionally structured contact springs are prone to overheating, melting, oxidation, and blackening under high current surges, which can even lead to electrode burnout or power outages.

[0006] Cylindrical lithium batteries of different specifications (such as 18650, 20700, 21700, 26800, 4680, etc.) have inconsistent end face dimensions, and the existing spring contact structure lacks universal adaptability, making it difficult to be compatible with multiple battery specifications at the same time, resulting in obvious limitations in use.

[0007] Therefore, there is an urgent need in the existing technology for an innovative spring sheet structure that is elastic and has a separate conductive path, is maintainable, replaceable, has low internal resistance, long lifespan, and can be adapted to multiple battery cell specifications, in order to solve the above problems. Summary of the Invention

[0008] The purpose of this invention is to provide an enhanced low internal resistance battery spring with a split structure. The spring adopts a design that separates the elastic structure and the conductive structure, so that the elastic element 2 provides a continuous and stable clamping force, while the conductive element 1 provides a low impedance conductive path, thereby solving the problems of elastic decay, increased contact resistance, end-face heating and blackening in the prior art.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: The conductive component 1 is made of phosphor bronze or copper with a nickel-plated surface treatment, with a thickness of 0.3–0.6 mm, and its shape can be sheet-like, arc-shaped, S-shaped, etc. The front end of the conductive component 1 forms an anti-blackening contact surface 3 for contacting the positive and negative electrodes of the battery, including the conductive component 1 and the elastic component 2. The conductive component 1 is disposed at the end of the battery, and the elastic component 2 is arranged inside the conductive component 1. The elastic component 2 can be a stainless steel cylindrical spring or a galvanized steel spring, located inside the conductive component 1 and providing axial elastic force, so that the conductive component 1 always maintains a stable contact pressure, allowing it to be independently replaced, maintained, or upgraded.

[0010] This structure ensures that elasticity and conductivity do not interfere with each other, maintaining long-term stability of elasticity while guaranteeing a low-resistance conductive path, thus improving safety and reliability in high-current applications. In addition, the split structure can be adapted to cylindrical lithium batteries of different sizes, enhancing versatility.

[0011] One of the beneficial effects of this invention is that the source of elasticity and the conductive path are completely separated, resulting in a significantly longer lifespan. Spring fatigue does not affect conductivity, and conductivity attenuation does not affect elasticity.

[0012] One of the beneficial effects of this invention is the significant reduction in internal resistance. The optimized thickness of the phosphor bronze / copper body and the contact structure make the internal resistance superior to that of the manganese steel spring sheet.

[0013] One of the advantages of this invention is its strong battery compatibility, allowing it to be adapted to cylindrical lithium batteries of different diameters and lengths.

[0014] One of the advantages of this invention is that it is detachable and maintainable, allowing for quick replacement of damaged spring clips without having to replace the entire battery compartment.

[0015] One of the beneficial effects of this invention is that it is not prone to blackening, has stable contact, and the nickel plating + large contact surface structure effectively reduces electric arc. Attached Figure Description

[0016] Figure 1 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (overall structural schematic diagram).

[0017] Figure 2 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (structural diagram of conductive component 1).

[0018] Figure 3 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (structural diagram of spring / elastic component 2).

[0019] Figure 4 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (split-type assembly schematic diagram).

[0020] Figure 5This is one of the structural schematic diagrams of Embodiment 1 of the present invention (installation method schematic diagram).

[0021] Figure 6 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (schematic diagram of its interaction with a cylindrical battery).

[0022] Figure 7 This is one of the structural schematic diagrams (top view) of Embodiment 1 of the present invention.

[0023] Figure 8 This is one of the structural schematic diagrams (bottom view) of Embodiment 1 of the present invention.

[0024] Figure 9 This is one of the structural schematic diagrams (front view) of Embodiment 1 of the present invention.

[0025] Figure 10 This is one of the structural schematic diagrams (rear view) of Embodiment 1 of the present invention.

[0026] Figure 11 This is one of the structural schematic diagrams (left view) of Embodiment 1 of the present invention.

[0027] Figure 12 This is one of the structural schematic diagrams of Embodiment 1 of the present invention (right view). Detailed Implementation

[0028] Example 1: Basic structural composition, as shown in Figure 1, this invention discloses a split-type elastic-enhanced low internal resistance conductive structure for cylindrical lithium batteries, comprising: a conductive component 1, an elastic component 2, an anti-blackening contact surface 3, a support and positioning structure 4, and a mounting clip 5. The conductive component 1 is disposed at the end of the battery and directly contacts the battery terminal; the elastic component 2 is located inside the conductive component 1, providing axial clamping force for the conductive component 1; the mounting clip 5 and the support and positioning structure 4 are used to fix the conductive component 1 and the elastic component 2 assembly within the battery compartment.

[0029] Example 2: Conductive component structure, material and thickness. Conductive component 1 is made of any of the following materials: copper (C1100 or equivalent conductivity ≥97% IACS), phosphor bronze (C5191, C5210, etc.). Preferably, a metal sheet with a thickness of 0.5mm to 0.6mm is used to ensure a current carrying capacity of 10A to 50A by maintaining the cross-sectional area. For the plating design, the surface of conductive component 1 is preferably nickel-plated with a plating thickness of 3–5 μm. Its advantages include: improved oxidation resistance, less susceptibility to blackening, improved resistance to arc erosion, and more stable contact resistance. For the contact geometry, the front end of the conductive component 1 is provided with an anti-blackening contact surface 3 that contacts the battery terminal, including but not limited to: arc-shaped protrusions, S... The shaped bent contact surface, multi-point protrusion structure, and planar + protrusion composite contact structure are geometrically optimized to: increase the effective contact area, disperse unit pressure, reduce local current density, significantly reduce arc generation, and ensure low temperature rise and long lifespan at the connection point; the conductive path characteristics, with the conductive components forming the main path of the entire current loop, feature high metal purity, low internal resistance, sufficient thickness, and a reasonable geometric resistance design, which can effectively reduce the overall internal resistance of the battery, making the structure suitable for high-current energy storage, power tools, drone charging, and other scenarios.

[0030] Example 3: Elastic component structure, elastic force source, elastic component 2 is completely independent of conductive component 1, its structure includes: cylindrical helical spring, conical spring, C-shaped spring, double spring system, galvanized steel spring, stainless steel metal spring; spring material can be: galvanized steel wire, stainless steel wire (304, 316), high carbon spring steel (65Mn, etc.); the elastic component does not participate in conduction, the spring does not carry current, it is only used to: apply axial pressure to conductive component 1, provide stable contact force, avoid fatigue attenuation problem after long-term use. Since the spring is completely isolated from the conductive path, the conductivity does not change with the attenuation of elastic force, fundamentally solving the problem of short service life of traditional leaf spring structure; spring compression design, the free height of the spring, working compression amount and elastic force value are adjusted according to different cylindrical battery sizes, adapted to: battery length 40~90mm, battery diameter 18~30mm, ensuring that sufficient contact pressure can still be obtained within the battery length tolerance of ±0.5~1mm.

[0031] Example 4: Installation structure. The spring assembly is assembled inside the battery compartment via the support and positioning structure 4. The installation method can be: slot fixing, press-in structure, hook engagement structure, double-sided positioning post structure, or U-groove fixing structure. The installation structure allows the conductive components to be: freely disassembled and quickly maintained; and to be able to replace conductive parts 1 or elastic parts 2 with different materials to adapt to other battery sizes. This perfectly solves the problem of the unmaintainability of traditional welded or riveted springs.

[0032] Example 5: Anti-blackening structural design. Traditional spring contacts are prone to arcing in high-current environments, causing blackening or ablation of the contact points. This invention avoids this problem by: using a nickel-plated layer for the conductive component 1; employing a multi-point contact structure for the anti-blackening contact surface 3 to reduce the current density at a single point; using a split structure to prevent the elastic component 2 from participating in the current, thus improving reliability; having a large thickness for the conductive component 1 to reduce resistance heating; and optimizing the structural geometry to ensure a uniform current density distribution. Tests have shown that this structure can operate continuously at currents of 20A to 40A for extended periods without significant temperature rise or blackening at the contact points.

[0033] Example 6: Adaptation to different cylindrical batteries. Since the conductive component 1 is formed from a metal sheet, its dimensions can be varied within the following range: length 10-30 mm, width 4-12 mm, thickness 0.3-0.6 mm. The elastic component 2 is optional: steel wire diameter 0.25-0.8 mm, free length 4-12 mm. Therefore, it can be adapted to all common cylindrical lithium batteries on the market, such as 18650, 20700, 21700, 26800, 32700, 4680, etc.

[0034] Example 7: Overall structural working principle: The battery is inserted into the battery slot, and the end of the battery presses against the conductive component 1. The spring in the elastic component 2 generates a stable reaction force, and the conductive component 1 maintains uniform and sufficient contact pressure. The current completes the efficient connection between the conductive component 1 and the battery end face. The spring in the elastic component 2 continuously compensates for the micro-displacement and tolerance of the battery, maintaining a low impedance and high reliability connection for a long time. The elastic force and the conductive path are completely decoupled, so that the conductive component 1 no longer fails due to elastic decay. High current will not damage the spring, and the contact impedance is stable for a long time without obvious thermal decay or oxidation blackening.

Claims

1. A split-type elastic-enhanced low internal resistance conductive structure for cylindrical lithium batteries, characterized in that, include: Conductive component 1, made of conductive metal material, is used to directly contact the terminals of a cylindrical lithium battery and form a current path. The elastic element 2, made of elastic material, is used to provide axial clamping force to the conductive element 1; wherein the conductive element 1 and the elastic element 2 are separate structures, the conductive element 1 undertakes all the conductive function and does not participate in elastic deformation, and the elastic element 2 provides all the mechanical pressure and does not participate in the conductive path and the elastic path.

2. The conductive structure according to claim 1, characterized in that: The conductive element 1 is configured as a sheet, an arc surface, or a rolled edge, with its front end forming a contact surface for fitting the battery terminal. The elastic element 2 is disposed inside the conductive element 1, and both are fixed in the battery compartment by the support and positioning structure 4 and the mounting clip 5.

3. The conductive structure according to claim 1, characterized in that: The elastic element 2 is any one of a helical spring, a double spring structure, a multi-turn spring, or a cylindrical spring, and is installed in the working cavity defined by the fixed structure.

4. The conductive structure according to claim 1, characterized in that: The conductive component 1 is made of copper, phosphor bronze, nickel-plated copper, silver-plated copper, or an equivalent highly conductive metal material.

5. The conductive structure according to claim 1, characterized in that: The elastic element 2 is made of spring steel, galvanized steel wire, stainless steel spring wire or other highly elastic materials.

6. The conductive structure according to claim 1, characterized in that: The conductive component 1 can be replaced or adjusted according to the electrode size of different cylindrical lithium batteries to adapt to batteries such as 18650, 20700, 21700, 26800, and 4680.

7. The conductive structure according to claim 1, characterized in that: The conductive component 1 can be removed or replaced from the fixed structure for maintenance, cleaning or replacement.

8. The conductive structure according to claim 1, characterized in that: The pressure applied by the battery to the conductive element 1 is transmitted backward through the elastic element 2, which does not directly contact the battery terminals, thereby preventing the spring from arcing, heating up, or blackening.

9. The conductive structure according to claim 1, characterized in that: Current flows from the battery terminals to the external circuit only through conductive component 1. No part of the elastic component 2 participates in current conduction, thereby stabilizing the conductive path and keeping the resistance at a low level.

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