Secondary battery
By employing elongated sheet-like current collectors and an insulation design in the secondary battery, the high-temperature problem at the connection between the current collector and the tab is solved, achieving efficient heat dissipation and improved safety of the battery, thus extending its service life and safety.
Patent Information
- Application Number
- CN202423031829.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2034-12-09
AI Technical Summary
When a secondary battery is charged and discharged at high rates, the high resistance at the connection between the current collector and the electrode tabs can cause localized overheating, affecting the battery capacity and lifespan.
The first and second current collectors adopt a long strip-shaped sheet structure to increase the contact area between the tabs and the current collectors. Through the conductive connection along the length of the electrode assembly, the current is distributed evenly, and the insulation design avoids short circuits and optimizes heat distribution.
It reduces the resistance and heat generation of the current collector, improves the cycle stability and lifespan of the battery, enhances safety performance, and meets the needs of battery miniaturization and weight reduction.
Smart Images
Figure CN223898539U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, specifically to secondary batteries. Background Technology
[0002] A secondary battery, also known as a rechargeable battery or accumulator, is a battery that can be recharged after discharge to reactivate its active materials and continue to be used. Inside a secondary battery, the electrode assembly has protruding tabs that are welded to a current collector, which is then welded to the terminals, allowing current to flow into or out of the electrode assembly. According to Joule's law, an object with resistance will heat up when current flows through it. Therefore, during the operation of a secondary battery, the current collector, responsible for carrying current, will inevitably heat up continuously. During high-rate charging and discharging, the continuous heating of the current collector generates a large amount of heat, which is transferred through the tabs to the electrode assembly, causing excessively high temperatures at the connection points. This can lead to electrochemical failures such as metal deposition, reducing the battery's capacity and lifespan.
[0003] Currently, products on the market often minimize the size of the current collector to reduce cost and weight. On one hand, this results in high resistance in the current collector itself, generating significant heat when the battery is powered on. On the other hand, since the current collector and the electrode tabs are welded together, their dimensions are related; a very small current collector also leads to a very small electrode tab, resulting in high resistance. Both factors contribute to excessively high localized temperatures within the battery. Utility Model Content
[0004] In view of this, this application provides a secondary battery to solve the problem of excessively high local temperature in the battery.
[0005] This application provides a secondary battery, including an electrode assembly, a first current collector, a second current collector, a first terminal post, and a second terminal post.
[0006] The electrode assembly has a first tab and a second tab with opposite polarities on one side along its height direction. A first current collector and a second current collector are stacked and insulated from each other along the height direction of the electrode assembly. Both the first and second current collectors are elongated sheet-like structures, and their length directions are consistent with the length direction of the electrode assembly. The first tab is electrically connected to the side of the first current collector opposite to the second current collector, and their contact surface extends along the length direction of the first current collector. The second tab is electrically connected to the side of the second current collector opposite to the first current collector, and their contact surface extends along the length direction of the second current collector. A first post and a second post are connected to the first current collector and the second current collector respectively, one-to-one.
[0007] Beneficial effects: Both the first and second current collectors are designed as elongated, sheet-like structures, which significantly extends the contact area between the first tab and the first current collector, as well as the contact area between the second tab and the second current collector. This increases the heat transfer width between the tab and the current collector, reduces the resistance between the current collector and the tab, and lowers the heat generation power, thus reducing the temperature rise during high-rate charging and discharging of the battery. Simultaneously, the elongated, sheet-like design of the current collector increases the heat dissipation area, and the conductive connection along the length of the electrode assembly makes the current distribution more uniform, reducing localized high temperatures caused by current concentration. This design effectively reduces the resistance change of the current collector under high-temperature environments, thereby improving the battery's cycle stability and lifespan.
[0008] In one alternative embodiment, the first current collector is located away from the electrode assembly, the second current collector is located close to the electrode assembly, and the second terminal block passes through the first current collector and is insulated from the first current collector.
[0009] Beneficial effects: The design of keeping the first current collector away from the electrode assembly and the second current collector close to the electrode assembly allows for a stacked design of the first and second current collectors, reducing the space occupied by the overall assembly. Furthermore, the design of the second terminal passing through the first current collector but being insulated from it ensures smooth current transmission while preventing short circuits caused by electrical contact between the second terminal and the first current collector, further improving battery safety.
[0010] In one optional embodiment, the length ratio of the contact surface between the first current collector and the first tab to the length of the electrode assembly is 0.5 to 0.9. And / or, the length ratio of the contact surface between the second current collector and the second tab to the length of the electrode assembly is 0.5 to 0.9.
[0011] Beneficial effects: By precisely controlling the ratio of the length of the contact surface between the current collector and the electrode tab to the length of the electrode assembly, an optimal balance between heat dissipation performance and manufacturing cost is achieved. While an excessively long contact surface can further improve heat dissipation, it increases cost and weight; conversely, an excessively short contact surface may lead to insufficient heat dissipation. Therefore, this ratio range ensures efficient heat dissipation of the current collector while avoiding unnecessary resource waste.
[0012] In one optional embodiment, the first tabs are configured as a pair, each pair of first tabs being folded towards the first current collector in the width direction and overlapping the upper surface of the first current collector. And / or, the second tabs are configured as a pair, each pair of second tabs being folded towards the second current collector in the width direction and fitting against the lower surface of the second current collector.
[0013] Beneficial effects: The folded design of the tabs not only increases the contact area with the current collector, but also adapts to the stacked position of the first and second current collectors, ensuring the rationality of the structural design, making the battery structure more compact and more integrated, which is conducive to the miniaturization and weight reduction of the battery pack.
[0014] In one optional embodiment, the two first tabs are respectively located on two opposite sides of the upper surface of the electrode assembly, a gap is provided between the two first tabs, and the two second tabs are respectively located between the two first tabs.
[0015] Beneficial effects: The relative positional arrangement of the tabs facilitates the connection between the tabs and the current collector, avoiding short circuits caused by contact between tabs with opposite polarities.
[0016] In an optional embodiment, an insulating pad is further included, disposed between the first current collector and the second current collector, wherein the two opposite side walls of the insulating pad along the height direction abut against the first current collector and the second current collector, respectively.
[0017] Beneficial effects: The insulating pad can achieve electrical insulation between the first current collector and the second current collector, preventing major safety risks caused by battery short circuits.
[0018] In one alternative embodiment, a top cover is further included, located above the first current collector, with the first electrode penetrating through the top cover and connected to the first current collector, and the second electrode penetrating through the top cover, the first current collector, and the insulating gasket and connected to the second current collector.
[0019] Beneficial effects: The through-type design of the first and second terminals makes the battery structure more compact and more integrated, which is conducive to the miniaturization and weight reduction of the battery pack.
[0020] In one optional embodiment, the thickness of both the first current collector and the second current collector is A, wherein 0.5mm ≤ A ≤ 3mm.
[0021] Beneficial effects: A well-designed thickness for the current collector ensures sufficient mechanical strength and conductivity while avoiding increased weight and cost due to excessive thickness. Furthermore, appropriate thickness helps improve the current collector's heat dissipation efficiency and reduces its resistance changes at high temperatures.
[0022] In one alternative implementation, at least one of the first tab and the second tab is configured as a profile to form a support structure.
[0023] Beneficial effects: The design of the profile tabs not only enhances their supporting strength and improves their heat dissipation performance, but also supports the first and second current collectors. The spacing between the second current collector and the battery cell facilitates connection between the second tab and the second current collector, while also promoting heat dissipation. This design makes the tabs less prone to deformation or damage when subjected to high currents, and allows for rapid heat dissipation to the external environment. This helps extend battery life and improve battery safety.
[0024] In one optional embodiment, the first current collector is located away from the electrode assembly, and the second current collector is located close to the electrode assembly. The projected area of the first current collector along its normal direction is greater than the projected area of the second current collector along its normal direction, and the second current collector is located at the middle position of the first current collector; or, the projected area of the first current collector along its normal direction is equal to the projected area of the second current collector along its normal direction, and the edges of the first current collector and the second current collector coincide.
[0025] Beneficial effects: By adjusting the projected area and relative position of the current collector, the heat distribution and current path inside the battery can be further optimized. This design helps reduce the temperature gradient of the current collector in high-temperature environments and reduces the impact of thermal stress on the battery structure. Simultaneously, it also helps improve the battery's energy density and power density, enabling the battery to provide higher energy output and faster charge / discharge rates in a smaller volume and weight. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0027] Figure 1 This is a schematic diagram of the structure of a secondary battery according to an embodiment of this application;
[0028] Figure 2 This is a front view of a secondary battery according to an embodiment of this application;
[0029] Figure 3 This is a schematic diagram of the structure of the first electrode and the second electrode in the embodiments of this application;
[0030] Figure 4 This is an exploded view of a secondary battery according to an embodiment of this application.
[0031] Explanation of reference numerals in the attached figures:
[0032] 1. Electrode assembly; 2. First electrode tab; 3. Second electrode tab; 4. First current collector; 5. Second current collector; 6. First pole post; 7. Second pole post; 8. Insulating gasket; 9. Top cover. Detailed Implementation
[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0034] The following is combined with Figures 1 to 4 This describes an embodiment of the present application.
[0035] According to an embodiment of this application, a secondary battery is provided, including an electrode assembly 1, a first current collector 4, a second current collector 5, a first terminal 6, and a second terminal 7.
[0036] The electrode assembly 1 has a first tab 2 and a second tab 3 on one side along its height direction, and the first tab 2 and the second tab 3 have opposite polarities. A first current collector 4 and a second current collector 5 are stacked and insulated from each other along the height direction of the electrode assembly 1. Both the first current collector 4 and the second current collector 5 are elongated sheet-like structures, and their length directions are consistent with the length direction of the electrode assembly 1. The length directions of the first tab 2 and the second tab 3 are consistent with the length directions of the first current collector 4 and the second current collector 5. One long side of the first tab 2 is electrically connected to the side of the long side of the first current collector 4 opposite to the second current collector 5, and their contact surface extends along the length direction of the first current collector 4. The other long side of the first tab 2 is electrically connected to the electrode assembly 1, and its contact surface extends along the length direction of the electrode assembly 1. One long side of the second tab 3 is electrically connected to the side of the long side of the second current collector 5 opposite to the first current collector 4, and the contact surface between the two extends along the length direction of the second current collector 5. The other long side of the second tab 3 is electrically connected to the electrode assembly 1, and the contact surface extends along the length direction of the electrode assembly 1. The first post 6 and the second post 7 are respectively connected to the first current collector 4 and the second current collector 5. Through the above-mentioned structure, during charging, the current can flow in from the first post 6, sequentially through the first current collector 4, the first tab 2, the electrode assembly 1, the second tab 3, and the second current collector 5, and flow out from the second post 7; or, during charging, the current can flow in from the second post 7, sequentially through the second current collector 5, the second tab 3, the electrode assembly 1, the first tab 2, and the first current collector 4, and flow out from the first post 6. That is, this application does not limit the polarity of the first electrode 2 and the second electrode 3. The first electrode 2 can be a positive electrode and the second electrode 3 can be a negative electrode, or the second electrode 3 can be a positive electrode and the first electrode 2 can be a negative electrode. The materials of the first current collector 4 and the first pole 6 are selected adaptively according to the polarity of the first electrode 2, and the materials of the second current collector 5 and the second pole 7 are selected adaptively according to the polarity of the second electrode 3.
[0037] In this embodiment, both the first current collector 4 and the second current collector 5 are configured as elongated sheet-like structures. This significantly extends the contact area between the first tab 2 and the first current collector 4, as well as the contact area between the second tab 3 and the second current collector 5. This increases the heat transfer width between the tab and the current collector, reduces the resistance between the current collector and the tab, and lowers the heat generation power, thus reducing the temperature rise during high-rate charging and discharging of the battery. Simultaneously, the elongated sheet-like design of the current collector increases the heat dissipation area, and the conductive connection along the length of the electrode assembly 1 makes the current distribution more uniform, reducing localized high temperatures caused by current concentration. This design effectively reduces the resistance change of the current collector under high-temperature environments, thereby improving the cycle stability and lifespan of the battery.
[0038] In some embodiments, the first current collector 4 may be disposed away from the electrode assembly 1, the second current collector 5 may be disposed close to the electrode assembly 1, the second pole post 7 passes through the first current collector 4 and is connected to the second current collector 5, and the second current collector 5 is insulated from the first current collector 4.
[0039] Optionally, a through hole may be provided on the first current collector 4 for the second pole 7 to pass through. A gap may be provided between the outer peripheral surface of the second pole 7 and the inner wall of the through hole to prevent the second pole 7 from contacting the first current collector 4 and causing a short circuit.
[0040] Optionally, a through hole may be provided on the first current collector 4 for the second terminal 7 to pass through. A gap may be provided between the outer peripheral surface of the second terminal 7 and the inner wall of the through hole, and insulating adhesive or an insulating coating may be provided in the gap to prevent short circuit between the second terminal 7 and the first current collector 4. The insulating adhesive may be applied to the first current collector 4, the second terminal 7, or both. The insulating coating may be applied to the first current collector 4, the second terminal 7, or both.
[0041] Optionally, through holes can also be provided on the second current collector 5 so that the first current collector 4 and the second current collector 5 have the same structure. In the actual assembly process, the same mold can be used to make the first current collector 4 and the second current collector 5, which improves production efficiency.
[0042] In this embodiment, the design of placing the first current collector 4 away from the electrode assembly 1 and the second current collector 5 close to the electrode assembly 1 enables the stacking of the first current collector 4 and the second current collector 5, reducing the space occupied by the overall assembly. Furthermore, the design of the second terminal 7 penetrating through the first current collector 4 but insulated from it ensures smooth current transmission and avoids short circuits caused by electrical contact between the second terminal 7 and the first current collector 4, further improving the battery's safety performance.
[0043] In some embodiments, the length ratio of the contact surface between the first current collector 4 and the first tab 2 to the length of the electrode assembly 1 is 0.5 to 0.9.
[0044] Optionally, the length ratio of the contact surface between the second current collector 5 and the second electrode tab 3 to the length of the electrode assembly 1 is 0.5 to 0.9.
[0045] In this embodiment, by precisely controlling the ratio of the length of the contact surface between the current collector and the tab to the length of the electrode assembly 1, an optimal balance between heat dissipation performance and manufacturing cost is achieved. While an excessively long contact surface can further improve heat dissipation, it increases cost and weight; conversely, an excessively short contact surface may lead to insufficient heat dissipation. Therefore, the design of this ratio range ensures efficient heat dissipation of the current collector while avoiding unnecessary resource waste.
[0046] In some embodiments, the first tabs 2 are configured as a pair, with each pair of first tabs 2 folded towards the first current collector 4 from the width direction of the first current collector 4 and overlapping the upper surface of the first current collector 4. Specifically, configuring the first tabs 2 as a pair can be achieved by providing two electrode assemblies 1, with one first tab 2 on each electrode assembly 1.
[0047] Optionally, the second tabs 3 are configured as a pair, with each pair of second tabs 3 folded towards the second current collector 5 from the width direction of the second current collector 5 and attached to the lower surface of the second current collector 5. Specifically, configuring the second tabs 32 as a pair can be achieved by configuring two electrode assemblies 1, with one second tab 3 on each electrode assembly 1.
[0048] Optionally, the first electrode 2 and the first current collector 4 can be welded together.
[0049] Optionally, the second electrode 3 and the second current collector 5 can be welded together.
[0050] In some embodiments, an insulating pad 8 is further included, disposed between the first current collector 4 and the second current collector 5, wherein the two opposite side walls of the insulating pad 8 along the height direction abut against the first current collector 4 and the second current collector 5, respectively.
[0051] In this embodiment, the insulating pad 8 can achieve electrical insulation between the first current collector 4 and the second current collector 5, preventing a major safety risk from a battery short circuit.
[0052] In some embodiments, a top cover 9 is also included, located above the first current collector 4. A first pole post 6 passes through the top cover 9 and is connected to the first current collector 4. A second pole post 7 passes through the top cover 9, the first current collector 4, and the insulating gasket 8 and is connected to the second current collector 5.
[0053] In this embodiment, the through-type design of the first terminal 6 and the second terminal 7 makes the battery structure more compact and the integration higher, which is beneficial to the miniaturization and weight reduction of the battery pack.
[0054] In some embodiments, the thickness of both the first current collector 4 and the second current collector 5 is A, wherein 0.5mm≤A≤3mm.
[0055] In this embodiment, the appropriate design of the current collector thickness ensures sufficient mechanical strength and conductivity while avoiding increased weight and cost due to excessive thickness. Furthermore, suitable thickness also helps improve the heat dissipation efficiency of the current collector and reduces its resistance changes under high-temperature environments.
[0056] In some embodiments, the two first tabs 2 are respectively located on two opposite sides of the upper surface of the electrode assembly 1, and a gap is provided between the two first tabs 2, and the two second tabs 3 are respectively located between the two first tabs 2.
[0057] In this embodiment, the relative position arrangement of the tabs facilitates the connection between the tabs and the current collector, avoiding short circuits caused by contact between tabs with opposite polarities.
[0058] In some embodiments, at least one of the first tab 2 and the second tab 3 is configured as a profile to form a support structure.
[0059] In this embodiment, the design of the profile tabs not only enhances the support strength of the tabs and improves their heat dissipation performance, but also supports the first current collector 4 and the second current collector 5. This creates a gap between the second current collector 5 and the battery cell, facilitating connection between the second tab 3 and the second current collector 5 while also promoting heat dissipation. This design makes the tabs less prone to deformation or damage when subjected to high current, and simultaneously allows for rapid heat dissipation to the external environment. This helps extend battery life and improve battery safety.
[0060] In some embodiments, the first current collector 4 is located away from the electrode assembly 1, and the second current collector 5 is located close to the electrode assembly 1. The projected area of the first current collector 4 along its normal direction is larger than the projected area of the second current collector 5 along its normal direction, and the second current collector 5 is located at the middle position of the first current collector 4. This results in the cross-sectional area of the first current collector 4 being larger than that of the second current collector 5.
[0061] Optionally, the projected area of the first current collector 4 along its normal direction is equal to the projected area of the second current collector 5 along its normal direction, and the edges of the first current collector 4 and the second current collector 5 coincide. This makes the cross-sectional area of the first current collector 4 equal to that of the second current collector 5, so the first current collector 4 and the second current collector 5 can be set to the same structure, improving production efficiency.
[0062] In this embodiment, by adjusting the projected area and relative position of the current collector, the heat distribution and current path inside the battery can be further optimized. This design helps reduce the temperature gradient of the current collector in high-temperature environments and reduces the impact of thermal stress on the battery structure. Simultaneously, it also helps improve the battery's energy density and power density, enabling the battery to provide higher energy output and faster charge / discharge rates with a smaller volume and weight.
[0063] Although embodiments of this application have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of this application, and all such modifications and variations fall within the scope defined by the appended claims.
Claims
1. A secondary battery, characterized in that, include: The electrode assembly (1) has a first electrode tab (2) and a second electrode tab (3) of opposite polarity on one side along the height direction; The first current collector (4) and the second current collector (5) are stacked along the height direction of the electrode assembly (1) and are insulated from each other. The first current collector (4) and the second current collector (5) are both configured as long strip-shaped sheet structures, and their length directions are consistent with the length direction of the electrode assembly (1). Wherein, the first electrode (2) is electrically connected to the side of the first current collector (4) away from the second current collector (5), and the contact surface of the two extends along the length direction of the first current collector (4); the second electrode (3) is electrically connected to the side of the second current collector (5) away from the first current collector (4), and the contact surface of the two extends along the length direction of the second current collector (5). The first pole (6) and the second pole (7) are respectively connected to the first current collector (4) and the second current collector (5).
2. The secondary battery according to claim 1, characterized in that: The first current collector (4) is away from the electrode assembly (1), the second current collector (5) is close to the electrode assembly (1), and the second pole post (7) passes through the first current collector (4) and is insulated from the first current collector (4).
3. The secondary battery according to claim 1, characterized in that: The length ratio of the contact surface between the first current collector (4) and the first electrode tab (2) to the length of the electrode assembly (1) is 0.5 to 0.
9. And / or, the length of the contact surface between the second current collector (5) and the second electrode tab (3) is 0.5 to 0.9 times the length of the electrode assembly (1).
4. The secondary battery according to claim 1, characterized in that: The first electrode tab (2) is configured as a pair, and the pair of first electrode tabs (2) are respectively folded from the width direction of the first current collector (4) toward the first current collector (4) and overlapped on the upper surface of the first current collector (4); And / or, the second electrode (3) is configured as a pair, the pair of second electrode (3) being folded towards the second current collector (5) from the width direction of the second current collector (5) and attached to the lower surface of the second current collector (5).
5. The secondary battery according to claim 4, characterized in that: The two first tabs (2) are located on opposite sides of the upper surface of the electrode assembly (1), and there is a gap between the two first tabs (2). The two second tabs (3) are located between the two first tabs (2).
6. The secondary battery according to claim 1, characterized in that, Also includes: An insulating pad (8) is disposed between the first current collector (4) and the second current collector (5), and the two side walls of the insulating pad (8) along the height direction respectively abut against the first current collector (4) and the second current collector (5).
7. The secondary battery according to claim 6, characterized in that, Also includes: The top cover (9) is located above the first current collector (4). The first pole post (6) passes through the top cover (9) and is connected to the first current collector (4). The second pole post (7) passes through the top cover (9), the first current collector (4) and the insulating pad (8) and is connected to the second current collector (5).
8. The secondary battery according to claim 1, characterized in that: The thickness of the first current collector (4) and the second current collector (5) is A, wherein 0.5mm≤A≤3mm.
9. The secondary battery according to claim 1, characterized in that: At least one of the first tab (2) and the second tab (3) is configured as a profile to form a support structure.
10. The secondary battery according to claim 1, characterized in that: The first current collector (4) is away from the electrode assembly (1), and the second current collector (5) is close to the electrode assembly (1). The projected area of the first current collector (4) along its normal direction is greater than the projected area of the second current collector (5) along its normal direction, and the second current collector (5) is located at the middle position of the first current collector (4); or, the projected area of the first current collector (4) along its normal direction is equal to the projected area of the second current collector (5) along its normal direction, and the edge positions of the first current collector (4) and the second current collector (5) coincide.