Battery end cover and shell connecting structure and battery

Abstract

The invention relates to a battery end cover and shell connecting structure and a battery, the battery end cover and shell connecting structure comprises a shell and an end cover arranged at the opening of the shell, an annular elastic embedding part is arranged at the position, close to the opening end, in the shell, and an annular clamping groove is formed in the elastic embedding part; the end cover is provided with an annular clamping groove part, the elastic embedding part is embedded in the clamping groove part, and an elastic annular protrusion embedded in the annular clamping groove is arranged in the clamping groove part. According to the invention, the annular nesting design of the elastic nesting part and the clamping groove part is matched with the interlocking structure of the elastic annular bulge and the annular clamping groove, so that a multi-stage sealing interface is formed, the internal pressure change and the external environment impact of the battery can be effectively resisted, and the air tightness and the liquid leakage prevention performance are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a connection structure between a battery end cover and a housing and a battery. Background Art

[0002] The basic principle of a lithium battery is mainly based on the movement of lithium ions between the positive electrode and the negative electrode. During charging, lithium ions are detached from the positive electrode material, migrate through the electrolyte to the negative electrode, and are embedded in the crystal lattice of the negative electrode material. At the same time, electrons travel from the positive electrode through the external circuit to the negative electrode, forming an electric current. This process enables the battery to store electrical energy. During discharging, lithium ions are deintercalated from the negative electrode material, return to the positive electrode through the electrolyte, and electrons return from the negative electrode through the external circuit to the positive electrode, releasing electrical energy for use by the device. This process of lithium ion migration between the positive and negative electrodes is reversible, so lithium ion batteries can be repeatedly charged and discharged.

[0003] The end cover of the existing lithium battery is directly welded to the housing. If there is poor welding during peripheral welding and it is not detected during airtightness testing, or if the end cover corrodes or is damaged due to collision around the battery during its service life, the seal between the housing and the end cover will be poor, and even the electrolyte inside the battery may leak, posing a great danger. Summary of the Invention

[0004] Based on this, the purpose of the present invention is to provide a connection structure between a battery end cover and a housing and a battery to solve a series of safety problems existing in the direct welding of the end cover of a lithium battery to the housing in the prior art.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention first provides a connection structure between a battery end cover and a housing, which includes a housing and an end cover provided at the opening of the housing. An annular elastic fitting portion is provided near the opening end inside the housing, and the elastic fitting portion is formed with an annular card slot; the end cover is provided with an annular clamping groove portion, and the elastic fitting portion is fitted in the clamping groove portion. An elastic annular protrusion is provided in the clamping groove portion and is fitted in the annular card slot.

[0006] Through the annular nesting design of the elastic fitting part and the clamping groove part, combined with the interlocking structure of the elastic annular protrusion and the annular clamping groove, the present invention forms a multi-level sealing interface, which can effectively resist the internal pressure change of the battery and the impact of the external environment, and significantly improve the airtightness and anti-leakage performance; the fitting part and the protrusion composed of elastic materials have the characteristics of deformation and rebound, which can automatically compensate for the dimensional fluctuations caused by assembly tolerances and temperature changes, and ensure the continuous and tight fit of the connection interface during long-term use; the circumferential constraint of the annular clamping groove combined with the multi-point biting of the elastic protrusion forms a three-dimensional limit structure, which can effectively inhibit the axial displacement and radial offset, and is particularly suitable for the application scenario of power batteries in high-frequency vibration environments; the integrated annular design realizes uniform stress distribution and avoids the problem of local stress concentration.

[0007] As a further improvement of the above solution of the present invention, the elastic fitting part includes an integrally formed elastic convex ring one and an elastic convex ring two, and the elastic convex ring one and the elastic convex ring two are arranged at intervals in the height direction of the housing to form an annular clamping groove therebetween.

[0008] As a further improvement of the above solution of the present invention, the elastic fitting part and the housing are integrally injection molded.

[0009] As a further improvement of the above solution of the present invention, the end cover includes an inner support cover and an outer pressure cover; the inner support cover is arranged inside the housing and below the elastic fitting part, and a fixing ring for supporting the inner support cover is arranged at the position below the inner wall of the housing; the outer pressure cover is arranged at the open end of the housing and is hermetically connected to the housing; a ring-shaped elastic member that abuts against the outer pressure cover is connected to the side of the inner support cover facing the outer pressure cover, a clamping groove part is formed between the inner support cover, the inner pressure cover and the ring-shaped elastic member, and an elastic annular protrusion is arranged on the outer peripheral surface of the ring-shaped elastic member. In the present invention, the split clamping structure formed by the inner support cover and the outer pressure cover, combined with the rigid support at the bottom of the fixing ring, forms an upper and lower double-layer sealing barrier at the housing-end cover connection interface: the inner support cover bears the main internal pressure of the battery through the fixing ring, and the outer pressure cover focuses on the external environment sealing, and the pressure grading transmission mechanism greatly reduces the risk of single-point failure. The ring-shaped elastic member, as a flexible medium layer, constructs an elastic stress buffer zone between the inner support cover and the outer pressure cover, which can not only absorb the impact of the internal air pressure pulsation during the charging and discharging process of the battery, but also disperse the assembly prestress between the housing and the end cover through elastic deformation, avoiding the expansion of microcracks caused by hard contact. The thermal expansion coefficient gradient design of the ring-shaped elastic member (low expansion in the inner layer and high elasticity in the outer layer) enables it to actively compensate for the deformation differences of dissimilar materials between the housing and the end cover when the temperature changes, eliminating the sealing gap caused by thermal cycling, and is particularly suitable for wide-temperature working conditions.

[0010] As a further improvement of the above solution of the present invention, a positive electrode post is arranged on the outer side surface of the outer pressure cover, and a flexible positive electrode connecting member is arranged between the outer pressure cover and the inner support cover. The positive electrode connecting member is in a Z-shaped structure and is electrically connected to the positive electrode post.

[0011] As a further improvement of the above solution of the present invention, a negative electrode post is provided on the outer side surface of the outer pressure cover, and a flexible negative electrode connecting member is provided between the outer pressure cover and the inner support cover. The negative electrode connecting members are all in a Z-shaped structure and are electrically connected to the negative electrode post.

[0012] As a further improvement of the above solution of the present invention, the outer pressure cover is made of plastic material and is heat-melted and connected to the housing. The outer pressure cover is made of plastic material, which realizes lightweight while ensuring structural strength. Its low thermal conductivity characteristic can block the thermal bridge effect of the metal material of the housing and reduce the risk of thermal runaway under extreme working conditions. The heat-melt connection between the outer pressure cover and the housing forms a molecular-level hermetic sealing interface, significantly improving the airtightness and anti-leakage performance.

[0013] As a further improvement of the above solution of the present invention, the fixing ring is integrally formed with the housing.

[0014] As a further improvement of the above solution of the present invention, the inner support cover is made of plastic material, and the annular elastic member is adhesively connected to the inner support cover. The inner support cover is made of plastic material, which realizes lightweight while ensuring structural strength.

[0015] The present invention also provides a battery, which includes the battery end cover and housing connection structure as described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: Through the annular nesting design of the elastic fitting part and the clamping groove part, and the interlocking structure of the elastic annular protrusion and the annular clamping groove, the present invention forms a multi-level sealing interface, which can effectively resist the internal pressure change of the battery and the impact of the external environment, and significantly improve the airtightness and anti-leakage performance; the fitting part and the protrusion composed of elastic materials have the characteristic of deformation and resilience, which can automatically compensate for the dimensional fluctuations caused by assembly tolerances and temperature changes, ensuring the continuous and tight fit of the connection interface during long-term use; the circumferential constraint of the annular clamping groove combined with the multi-point biting of the elastic protrusion forms a three-dimensional limit structure, which can effectively inhibit the axial displacement and radial offset, and is particularly suitable for the application scenario of power batteries in a high-frequency vibration environment; the integrated annular design realizes uniform force distribution and avoids the problem of local stress concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic structural diagram of a battery proposed in an embodiment of the present invention; Figure 2 It is a partial cross-sectional view of a battery proposed in an embodiment of the present invention.

[0018] Reference numerals: 100, housing; 110, elastic fitting portion; 111, first elastic convex ring; 112, second elastic convex ring; 120, fixing ring; 200, end cap; 210, clamping groove portion; 220, elastic annular protrusion; 230, inner support cover; 240, outer pressing cover; 250, annular elastic member; 260, positive electrode post; 270, positive electrode connecting member; 270, negative electrode post; 300, battery cell. Detailed implementation manners

[0019] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] Referring to Figure 1 、 Figure 2 , this embodiment provides a battery, which includes a housing 100, an end cap 200 and a battery cell.

[0022] The top of the housing 100 is open, and the housing 100 can be made of stainless steel or aluminum alloy. An annular elastic fitting portion 110 is provided inside the housing 100 near its open end. The elastic fitting portion 110 includes an integrally formed first elastic convex ring 112 and a second elastic convex ring 113. The first elastic convex ring 112 and the second elastic convex ring 113 are spaced apart in the height direction of the housing 100 to form an annular card slot 111 therebetween. In this embodiment, the elastic fitting portion 110 is made of a polymer material (such as synthetic rubber), and the elastic fitting portion 110 and the housing 100 can be integrally injection molded. A fixing ring 120 is provided inside the housing 100 at a position below the elastic fitting portion 110, and the fixing ring 120 is integrally formed with the housing 100.

[0023] The end cap 200 includes an inner support cap 230 and an outer pressing cap 240. The inner support cap 230 is disposed inside the housing 100 and below the elastic fitting portion 110, and is supported and fixed by the fixing ring 120. The upper end surface of the inner support cap 230 contacts a part of the lower end surface of the elastic fitting portion 110. A ring-shaped elastic member 250 is connected to the upper end surface of the inner support cap 230, and an elastic ring-shaped protrusion 220 is provided on the outer peripheral surface of the ring-shaped elastic member 250. In this embodiment, the inner support cap 230 can be made of a plastic material (such as PEEK or glass fiber-reinforced nylon), the ring-shaped elastic member 250 is made of a polymer material (such as synthetic rubber), and the ring-shaped elastic member 250 and the inner support cap 230 can be adhesively connected. The outer pressing cap 240 is disposed in the opening of the housing 100. The outer pressing cap 240 can be made of a plastic material (such as PEEK or glass fiber-reinforced nylon) and is heat-melt connected to the housing 100. The ring-shaped elastic member 250 abuts against the inner surface of the outer pressing cap 240 to form a clamping groove portion 210 between the inner support cap 230, the inner pressing cap and the ring-shaped elastic member 250. The elastic fitting portion 110 is embedded in the clamping groove portion 210, and the elastic ring-shaped protrusion 220 is embedded in the annular card slot 111 of the elastic fitting portion 110. A positive electrode post 260 and a negative electrode post are provided on the outer pressing cap 240. A flexible positive electrode connecting member 270 and a negative electrode connecting member are provided between the outer pressing cap 240 and the inner support cap 230. The positive electrode connecting member 270 and the negative electrode connecting member are both in a Z-shaped structure, so that the positive electrode connecting member 270 and the negative electrode connecting member can expand and contract and the positive electrode connecting member 270 and the negative electrode connecting member are made of a conductive material. The positive electrode connecting member 270 and the negative electrode connecting member are respectively welded to the positive electrode post 260 and the negative electrode post. The welding method can refer to the prior art and will not be elaborated here.

[0024] The battery cell is disposed inside the housing 100. The battery cell has a positive electrode tab and a negative electrode tab. The positive electrode connecting member 270 and the negative electrode connecting member are respectively welded to the positive electrode tab and the negative electrode tab, and insulation is maintained between the positive electrode connecting member 270, the negative electrode connecting member and the inner support cap 230. Openings can be made on the inner support cap 230 for welding the positive electrode connecting member 270 to the positive electrode tab and the negative electrode connecting member to the negative electrode tab respectively. The welding method can refer to the prior art and will not be elaborated here.

[0025] With the above structural settings, the battery assembly method of the present invention is as follows: After the housing 100 is formed, the wound battery cell is first assembled into the housing from the open end of the housing 100; then the inner support cover 230 with the annular elastic member 250 is assembled into the housing. The size of the inner support cover 230 needs to be reasonably set according to the size of the elastic fitting portion 110 to ensure that the inner support cover 230 can be assembled into the housing. During this process, the elastic annular protrusion 220 of the annular elastic member 250 can be fitted into the annular card slot 111 of the elastic fitting portion 110; then the positive connection member 270 and the negative connection member are respectively welded to the positive electrode tab and the negative electrode tab of the battery cell; finally, the outer pressure cover 240 is assembled, the outer pressure cover 240 is assembled into the opening of the housing 100, and the annular elastic member 250 is squeezed, and then the outer pressure cover 240 is heat-melted and connected to the housing 100. Finally, the positive terminal 260 and the negative terminal are respectively welded to the positive connection member 270 and the negative connection member.

[0026] It should be noted that when a component is referred to as being "mounted on" another component, it can be directly on the other component or there may also be an intermediate component. When a component is considered to be "disposed on" another component, it can be directly disposed on the other component or there may be an intermediate component at the same time. When a component is considered to be "fixed to" another component, it can be directly fixed to the other component or there may be an intermediate component at the same time.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this invention belongs. The terms used in the description of the present invention in this specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0028] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0029] The above-described embodiments only represent several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it cannot be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. A connection structure between a battery end cover and a housing, which includes a housing (100) and an end cover (200) arranged at the opening of the housing (100), and is characterized in that, Inside the housing (100) near its open end, there is a ring-shaped elastic fitting part (110), and the elastic fitting part (110) is formed with an annular clamping groove; the end cover (200) is provided with a ring-shaped clamping groove part (210), and the elastic fitting part (110) is embedded in the clamping groove part (210), and an elastic ring-shaped protrusion (220) embedded in the annular clamping groove is arranged in the clamping groove part (210).

2. The battery end cover and housing connection structure according to claim 1, wherein The elastic fitting part (110) includes an integrally formed first elastic convex ring (111) and a second elastic convex ring (112), and the first elastic convex ring (111) and the second elastic convex ring (112) are arranged at intervals in the height direction of the housing (100) to form an annular clamping groove therebetween.

3. The battery end cover and housing connection structure according to claim 1, characterized in that, The elastic fitting part (110) and the housing (100) are formed by integral injection molding.

4. The battery end cover and housing connection structure according to claim 1, characterized in that, The end cover (200) includes an inner support cover (230) and an outer pressing cover (240); the inner support cover (230) is arranged inside the housing (100) and below the elastic fitting part (110), and a fixing ring (120) for supporting the inner support cover (230) is arranged at the position below the inner support cover (230) on the inner wall of the housing (100); the outer pressing cover (240) is arranged at the open end of the housing (100) and is hermetically connected to the housing (100); a ring-shaped elastic member (250) pressing against the outer pressing cover (240) is connected to the side of the inner support cover (230) facing the outer pressing cover (240), a clamping groove part (210) is formed among the inner support cover (230), the inner pressing cover, and the ring-shaped elastic member (250), and an elastic ring-shaped protrusion (220) is arranged on the outer peripheral surface of the ring-shaped elastic member (250).

5. The battery end cover and housing connection structure according to claim 4, characterized in that, A positive electrode post (260) is arranged on the outer side surface of the outer pressing cover (240), a flexible positive electrode connecting member (270) is arranged between the outer pressing cover (240) and the inner support cover (230), the positive electrode connecting member (270) is in a Z-shaped structure, and the positive electrode connecting member (270) is electrically connected to the positive electrode post (260).

6. The battery end cover and housing connection structure according to claim 4, characterized in that, A negative electrode post (270) is arranged on the outer side surface of the outer pressing cover (240), flexible negative electrode connecting members are arranged between the outer pressing cover (240) and the inner support cover (230), the negative electrode connecting members are all in Z-shaped structures, and the negative electrode connecting members are electrically connected to the negative electrode post (270).

7. The battery end cover and housing connection structure according to claim 4, characterized in that, The outer pressing cover (240) is made of plastic material and is heat-melted and connected to the housing (100).

8. The battery end cover and housing connection structure according to claim 4, wherein, The fixing ring (120) and the housing (100) are integrally formed.

9. The battery end cover and housing connection structure according to claim 4, characterized in that, The inner support cover (230) is made of plastic material, and the ring-shaped elastic member (250) is adhesively connected to the inner support cover (230).

10. A battery, characterized in that, It includes the battery end cover and housing connection structure according to any one of claims 1-9.

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