Battery cell and battery module
By employing an alternating layering structure of composite current collector electrodes and metal current collector electrodes in the battery cell, combined with the circuit-breaking effect of the polymer layer, the problems of reduced heat dissipation capacity and increased internal resistance caused by the reduction in the amount of metal current collector are solved, thus achieving high energy density, low internal resistance and high safety of the battery cell.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- EVE ENERGY CO LTD
- Filing Date
- 2025-05-28
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies, when reducing the amount of metal current collector in battery cells, result in decreased heat dissipation capacity and increased internal resistance, affecting battery performance and safety.
The structure of alternating layers of composite current collector electrode and metal current collector electrode is adopted to reduce the amount of metal current collector. A polymer layer is used in the composite current collector electrode to break the circuit at high temperature, forming a circuit breaking effect to prevent thermal runaway, while maintaining the conductivity and heat dissipation capacity of the metal current collector.
It improves the weight energy density and safety of the battery cell, reduces internal resistance and enhances heat dissipation, thereby reducing the risk of thermal runaway.
Smart Images
Figure CN224342280U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of battery technology, and in particular to a battery cell and a battery unit. Background Technology
[0002] With the continuous development of battery technology, people are paying more and more attention to improving the weight energy density and safety of batteries.
[0003] One way to increase the weight energy density of a battery is to reduce the amount of metal current collector used in the cell. The current common practice is to reduce the thickness of the metal current collector, but this will reduce the heat dissipation capacity of the cell and increase the internal resistance of the cell, thus degrading the battery performance.
[0004] Therefore, there is an urgent need to propose a new type of battery cell and battery unit to solve the above-mentioned technical problems. Utility Model Content
[0005] The first objective of this invention is to provide a battery cell that can improve the weight energy density and safety of the battery cell, and also enable the battery cell to have lower internal resistance and higher heat dissipation capacity.
[0006] To achieve this objective, the present invention adopts the following technical solution:
[0007] Battery cells, including:
[0008] The composite current collector electrode portion includes a plurality of composite current collector electrodes stacked together, and the composite current collector electrode portion includes a first composite current collector portion and a second composite current collector portion.
[0009] The metal current collector electrode portion includes a plurality of stacked metal current collector electrodes, and the metal current collector electrode portion is located between the first composite current collector portion and the second composite current collector portion.
[0010] Optionally, some of the multiple composite current collectors are composite positive current collectors, and the rest are composite negative current collectors, with the composite positive current collectors and composite negative current collectors being stacked alternately.
[0011] Optionally, the composite positive current collector electrode includes a first composite current collector and two first positive active material layers, the two first positive active material layers respectively covering the opposite two sides of the first composite current collector;
[0012] The composite negative current collector electrode includes a second composite current collector and two first negative active material layers, which respectively cover the opposite two sides of the second composite current collector.
[0013] Optionally, the first composite current collector includes a first polymer layer and two first metal layers, with the two first metal layers respectively covering opposite sides of the first polymer layer;
[0014] The second composite current collector includes a second polymer layer and two second metal layers, with the two second metal layers respectively covering opposite sides of the second polymer layer.
[0015] Optionally, both the first polymer layer and the second polymer layer are PP layers.
[0016] Optionally, the thickness of the first polymer layer is 0.8 μm-5.2 μm, and the thickness of the first metal layer is 0.48 μm-2.2 μm;
[0017] The thickness of the second polymer layer is 0.8μm-5.2μm, and the thickness of the second metal layer is 0.48μm-2.2μm.
[0018] Optionally, some of the multiple metal current collectors are positive metal current collectors, and the rest are negative metal current collectors, with the positive and negative metal current collectors being stacked alternately.
[0019] Optionally, the metal positive current collector electrode includes a first metal current collector and two second positive active material layers, the two second positive active material layers respectively covering the opposite two sides of the first metal current collector;
[0020] The metal negative electrode current collector includes a second metal current collector and two second negative electrode active material layers, which respectively cover the opposite two sides of the second metal current collector.
[0021] Optionally, the thickness of the first metal current collector is 5.8μm-12.2μm, and the thickness of the second metal current collector is 2.8μm-6.2μm.
[0022] Optionally, the sum of the number of composite current collectors in the first composite current collector section and the number of composite current collectors in the second composite current collector section is A, and the number of metal current collectors is B, wherein 8% ≤ A / (A+B) ≤ 72%.
[0023] The second objective of this invention is to provide a battery cell that can improve the weight energy density and safety of the battery cell, and also enable the battery cell to have lower internal resistance and higher heat dissipation capacity.
[0024] To achieve this objective, the present invention adopts the following technical solution:
[0025] A battery cell includes a casing and the aforementioned battery cell, with the battery cell housed within the casing.
[0026] The beneficial effects of this utility model are:
[0027] Compared to structures where all electrodes are metal current collectors, the structure with the metal current collector located between the first and second composite current collector sections reduces the number of metal current collectors, thus reducing the amount of metal current collector used and increasing the cell's weight energy density. When the cell is pinned or the cell temperature is too high, the composite current collector exhibits an open-circuit effect, causing an internal circuit break and preventing further thermal runaway, thereby improving cell safety. The metal current collector in the metal current collector has excellent conductivity and heat dissipation capabilities, resulting in lower internal resistance and higher heat dissipation. Furthermore, when the cell is pinned or the cell temperature is too high, the temperature distribution shows a significant increase in the temperature in the middle compared to the sides. This large temperature gradient, combined with the structure where the middle region of the cell is a metal current collector, allows heat to be quickly transferred from the middle to the sides, achieving rapid cooling of the middle region and reducing the risk of thermal runaway, thus improving cell safety. Attached Figure Description
[0028] Figure 1 This is a cross-sectional structural diagram of the battery cell provided by this utility model;
[0029] Figure 2 This is a schematic cross-sectional view of the composite positive current collector electrode provided by this utility model.
[0030] Figure 3 This is a schematic cross-sectional view of the composite negative electrode current collector provided by this utility model.
[0031] Figure 4 This is a schematic cross-sectional view of the metal positive current collector electrode provided by this utility model.
[0032] Figure 5 This is a cross-sectional structural diagram of the metal negative electrode current collector provided by this utility model.
[0033] In the picture:
[0034] 1. Composite current collector electrode section; 11. Composite positive current collector electrode; 111. First composite current collector; 1111. First polymer layer; 1112. First metal layer; 112. First positive active material layer; 12. Composite negative current collector electrode; 121. Second composite current collector; 1211. Second polymer layer; 1212. Second metal layer; 122. First negative active material layer; 13. First separator; 2. Metal current collector electrode section; 21. Metal positive current collector electrode; 211. First metal current collector; 212. Second positive active material layer; 22. Metal negative current collector electrode; 221. Second metal current collector; 222. Second negative active material layer; 23. Second separator; 3. Third separator. Detailed Implementation
[0035] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.
[0036] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0038] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.
[0039] This embodiment provides a battery cell that can improve the weight energy density and safety of the battery cell, and also enable the battery cell to have lower internal resistance and higher heat dissipation capacity.
[0040] Specifically, such as Figure 1 As shown, the battery cell includes a composite current collector electrode portion 1 and a metal current collector electrode portion 2. The composite current collector electrode portion 1 includes multiple composite current collector electrodes stacked together, including a first composite current collector electrode portion and a second composite current collector electrode portion. The metal current collector electrode portion 2 includes multiple metal current collector electrodes stacked together, and the metal current collector electrode portion 2 is located between the first composite current collector electrode portion and the second composite current collector electrode portion. That is, there are two composite current collector electrode portions 1, and the metal current collector electrode portion 2 is located between the two composite current collector electrode portions 1.
[0041] Compared to structures where all electrodes are metal current collectors, the structure where the metal current collector electrode portion 2 is located between the first and second composite current collector portions reduces the number of metal current collectors, thus reducing the amount of metal current collector used and improving the cell's weight energy density. When the cell is pinned or the cell temperature is too high, the composite current collector electrode exhibits an open-circuit effect, causing an internal circuit break and preventing further thermal runaway, thereby improving cell safety. The metal current collector in the metal current collector electrode has good conductivity and heat dissipation capabilities, resulting in lower internal resistance and higher heat dissipation capacity for the cell. Furthermore, when the cell is pinned or the cell temperature is too high, the temperature distribution shows that the temperature in the middle is significantly higher than the temperatures on both sides. This large temperature gradient, combined with the structure where the middle region of the cell is a metal current collector electrode, allows heat to be quickly transferred from the middle region to both sides of the cell, achieving rapid cooling of the middle region and reducing the risk of thermal runaway, thus improving cell safety.
[0042] Optionally, the sum of the number of composite current collectors in the first composite current collector section and the number of composite current collectors in the second composite current collector section is A, that is, the sum of the number of composite current collectors in the two composite current collector sections 1 is A, and the number of metal current collectors is B, wherein 8% ≤ A / (A+B) ≤ 72%. For example, A / (A+B) can be 8%, 10%, 30%, 55%, 70%, or 72%, etc. If A / (A+B) is less than 8%, the number of composite current collectors is too small and the number of metal current collectors is too large, thereby reducing the weight energy density of the cell. If A / (A+B) is greater than 72%, the number of composite current collectors is too large and the number of metal current collectors is too small, thereby increasing the internal resistance of the cell and reducing the heat dissipation capacity of the cell. By controlling A / (A+B) between 8% and 72%, the internal resistance and heat dissipation capacity of the cell can be considered at the same time while improving the weight energy density of the cell. It should be noted that the specific value of A / (A+B) can be determined based on the actual performance and safety requirements of the battery cells.
[0043] Optionally, a portion of the multiple composite current collectors is a composite positive current collector 11, and the remaining portion is a composite negative current collector 12, with the composite positive current collector 11 and the composite negative current collector 12 being stacked alternately.
[0044] Furthermore, such as Figure 2 As shown, the composite positive current collector electrode 11 includes a first composite current collector 111 and two first positive active material layers 112. The two first positive active material layers 112 respectively cover the opposite two sides of the first composite current collector 111 to form the composite positive current collector electrode 11; as shown Figure 3 As shown, the composite negative current collector electrode 12 includes a second composite current collector 121 and two first negative current active material layers 122. The two first negative current active material layers 122 respectively cover the opposite two sides of the second composite current collector 121 to form the composite negative current collector electrode 12.
[0045] Furthermore, such as Figure 2 As shown, the first composite current collector 111 includes a first polymer layer 1111 and two first metal layers 1112, with the two first metal layers 1112 respectively covering opposite side surfaces of the first polymer layer 1111; as Figure 3 As shown, the second composite current collector 121 includes a second polymer layer 1211 and two second metal layers 1212, with the two second metal layers 1212 respectively covering the opposite two sides of the second polymer layer 1211.
[0046] Furthermore, both the first polymer layer 1111 and the second polymer layer 1211 are PP (polypropylene) layers. PP material has a low melting point. When the temperature of the battery cell reaches about 150°C, the PP layer melts and breaks, resulting in a circuit break effect. This causes an internal circuit break in the battery cell, preventing further thermal runaway. It can be seen that using PP layers as the first polymer layer 1111 and the second polymer layer 1211 can improve the safety of the battery cell. Of course, in other embodiments, the first polymer layer 1111 and the second polymer layer 1211 can also be terephthalate, polyamide, polyimide, polyethylene, polystyrene, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, poly(p-phenylene terephthalate), polypropylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol formaldehyde, polyvinyl butyral, polyurethane, polyurethane, polyacrylonitrile, polyvinyl acetate, polyoxymethylene, phenolic resin, epoxy resin, polytetrafluoroethylene, polyvinylidene fluoride, polycarbonate, polysulfone, polyethersulfone, or polyphenylene ether, etc., and the materials of the first polymer layer 1111 and the second polymer layer 1211 can be the same or different, depending on the actual application requirements.
[0047] It should be noted that the above-mentioned circuit breaking effect is common knowledge in the field. For example, when the cell is pierced or the cell temperature is too high, the first polymer layer 1111 (or the second polymer layer 1211) tears and melts, and the first metal layer 1112 and the first positive electrode active material layer 112 (or the second metal layer 1212 and the first negative electrode active material layer 122) crack under the dual action of tensile stress and adhesion binding force, thereby forming a circuit breaking.
[0048] Optionally, the thickness of the first polymer layer 1111 is 0.8μm-5.2μm. For example, the thickness of the first polymer layer 1111 can be 0.8μm, 1.0μm, 2.0μm, 5μm, or 5.2μm, etc., and the thickness of the first metal layer 1112 is 0.48μm-2.2μm. For example, the thickness of the first metal layer 1112 can be 0.48μm, 0.5μm, 1.0μm, 2.0μm, or 2.2μm, etc., so that the first polymer layer... The thickness of the first composite current collector 1111 is relatively large, while the thickness of the first metal layer 1112 is relatively small, in order to minimize the weight of the first composite current collector 111 and achieve the effect of increasing the weight energy density of the battery cell. Furthermore, in practical applications, it is sufficient for the first metal layer 1112 to function as a conductor. The first polymer layer 1111 bears the greatest tensile stress in the first composite current collector 1111. The thicker first polymer layer 1111 has higher structural strength, which can avoid the problem of the first polymer layer 1111 breaking during production.
[0049] The thickness of the second polymer layer 1211 is 0.8μm-5.2μm. For example, the thickness of the second polymer layer 1211 can be 0.8μm, 1.0μm, 2.0μm, 5μm, or 5.2μm, etc. The thickness of the second metal layer 1212 is 0.48μm-2.2μm. For example, the thickness of the second metal layer 1212 can be 0.48μm, 0.5μm, 1.0μm, 2.0μm, or 2.2μm, etc. This makes the thickness of the second polymer layer 1211 larger and the thickness of the second metal layer 1212 smaller, so as to minimize the weight of the second composite current collector 121 and achieve the effect of improving the weight energy density of the battery cell. In practical applications, it is sufficient for the second metal layer 1212 to have a conductive function. The second polymer layer 1211 bears the greater tensile stress in the second composite current collector 121. The thicker second polymer layer 1211 has higher structural strength, which can avoid the problem of the second polymer layer 1211 breaking during production.
[0050] Optionally, the first metal layer 1112 is an aluminum layer, which is electroplated onto the first polymer layer 1111, and the first positive electrode active material layer 112 is coated onto the side of the first metal layer 1112 opposite to the first polymer layer 1111. The second metal layer 1212 is a copper layer, which is electroplated onto the second polymer layer 1211, and the first negative electrode active material layer 122 is coated onto the side of the second metal layer 1212 opposite to the second polymer layer 1211. In other embodiments, the first metal layer 1112 may also be a nickel or silver layer, and the second metal layer 1212 may also be a nickel-copper alloy or a titanium layer.
[0051] Optionally, such as Figure 1 As shown, some of the multiple metal current collectors are positive metal current collectors 21, and the rest are negative metal current collectors 22. The positive metal current collectors 21 and the negative metal current collectors 22 are stacked alternately.
[0052] Furthermore, such as Figure 4 As shown, the metal positive current collector electrode 21 includes a first metal current collector 211 and two second positive active material layers 212. The two second positive active material layers 212 respectively cover the opposite two side surfaces of the first metal current collector 211 to form the metal positive current collector electrode 21; as shown Figure 5 As shown, the metal negative electrode current collector 22 includes a second metal current collector 221 and two second negative electrode active material layers 222. The two second negative electrode active material layers 222 respectively cover the opposite two sides of the second metal current collector 221 to form the metal negative electrode current collector 22.
[0053] Optionally, the thickness of the first metal current collector 211 is 5.8μm-12.2μm. For example, the thickness of the first metal current collector 211 can be 5.8μm, 6μm, 10μm, 12μm or 12.2μm, etc., and the thickness of the second metal current collector 221 is 2.8μm-6.2μm. For example, the thickness of the second metal current collector 221 can be 2.8μm, 3μm, 5μm, 6μm or 6.2μm, etc., to ensure that the first metal current collector 211 and the second metal current collector 221 have sufficient structural strength and avoid breakage during production.
[0054] Optionally, the first metal current collector 211 is an aluminum foil, the second positive electrode active material layer 212 is coated onto the first metal current collector 211, the second metal current collector 221 is a copper foil, and the second negative electrode active material layer 222 is coated onto the second metal current collector 221. In other embodiments, the first metal current collector 211 can be a metal current collector such as nickel or silver, and the second metal current collector 221 can be a nickel-copper alloy or a metal current collector such as titanium.
[0055] Optionally, such as Figure 1 As shown, the composite current collector electrode section 1 also includes a first separator 13, which is sandwiched between each adjacent composite positive current collector electrode 11 and composite negative current collector electrode 12. The metal current collector electrode section 2 also includes a second separator 23, which is sandwiched between each adjacent metal positive current collector electrode 21 and metal negative current collector electrode 22. The battery cell also includes a third separator 3, which is sandwiched between the composite current collector electrode section 1 and the metal current collector electrode section 2 to prevent internal short circuits in the battery cell. The first separator 13, the second separator 23, and the third separator 3 can be polyethylene films or polypropylene films. Furthermore, the materials of the first separator 13, the second separator 23, and the third separator 3 can be the same or different, depending on the actual application requirements.
[0056] When preparing the battery cell provided in this embodiment, the Z-type stacking method commonly used in the art is adopted. First, composite current collector electrodes are stacked, then metal current collector electrodes are stacked, and finally composite current collector electrodes are stacked again. This creates a structure in which the metal current collector electrode portion 2 is located between the first composite current collector portion and the second composite current collector portion. This "sandwich" battery cell structure can not only improve the weight energy density and safety of the battery cell, but also minimize the degradation of the battery cell's impedance and simultaneously optimize the battery cell's heat dissipation capability.
[0057] This embodiment also provides a battery cell, which includes a casing and the aforementioned battery cell. The battery cell is disposed inside the casing. By using the aforementioned battery cell, the amount of metal current collector is reduced, thereby reducing the weight of the battery cell and the battery cell, and achieving the effect of increasing the weight energy density of the battery cell. When the battery cell is punctured or the internal temperature is too high, the composite current collector electrode exhibits an open circuit effect, causing an internal circuit break within the battery cell and preventing further thermal runaway, thus giving the battery cell high safety. The metal current collector of the metal current collector electrode has good conductivity and heat dissipation capabilities, so the battery cell has low internal resistance and high heat dissipation capabilities. In addition, when the battery cell is punctured or the internal temperature is too high, the metal current collector electrode located in the middle region of the battery cell can rapidly cool down the middle region of the battery cell, reducing the risk of thermal runaway of the battery cell.
[0058] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.
Claims
1. A battery cell, characterized in that, include: The composite current collector electrode section (1) includes a plurality of composite current collector electrodes stacked together, and the composite current collector electrode section (1) includes a first composite current collector section and a second composite current collector section; The metal current collector electrode portion (2) includes a plurality of stacked metal current collector electrodes, and the metal current collector electrode portion (2) is located between the first composite current collector portion and the second composite current collector portion.
2. The battery cell according to claim 1, characterized in that, A portion of the multiple composite current collectors is a composite positive current collector (11), and the remaining portion is a composite negative current collector (12). The composite positive current collector (11) and the composite negative current collector (12) are stacked alternately.
3. The battery cell according to claim 2, characterized in that, The composite positive current collector electrode (11) includes a first composite current collector (111) and two first positive active material layers (112), with the two first positive active material layers (112) respectively covering the opposite two sides of the first composite current collector (111); The composite negative current collector electrode (12) includes a second composite current collector (121) and two first negative active material layers (122), with the two first negative active material layers (122) respectively covering the opposite two sides of the second composite current collector (121).
4. The battery cell according to claim 3, characterized in that, The first composite current collector (111) includes a first polymer layer (1111) and two first metal layers (1112), with the two first metal layers (1112) respectively covering the opposite two sides of the first polymer layer (1111); The second composite current collector (121) includes a second polymer layer (1211) and two second metal layers (1212), with the two second metal layers (1212) respectively covering the opposite two sides of the second polymer layer (1211).
5. The battery cell according to claim 4, characterized in that, Both the first polymer layer (1111) and the second polymer layer (1211) are PP layers.
6. The battery cell according to claim 4, characterized in that, The thickness of the first polymer layer (1111) is 0.8μm-5.2μm, and the thickness of the first metal layer (1112) is 0.48μm-2.2μm; The thickness of the second polymer layer (1211) is 0.8μm-5.2μm, and the thickness of the second metal layer (1212) is 0.48μm-2.2μm.
7. The battery cell according to any one of claims 1-6, characterized in that, A portion of the plurality of metal current collectors is a positive metal current collector (21), and the remainder is a negative metal current collector (22). The positive metal current collector (21) and the negative metal current collector (22) are stacked alternately.
8. The battery cell according to claim 7, characterized in that, The metal positive current collector electrode (21) includes a first metal current collector (211) and two second positive active material layers (212), with the two second positive active material layers (212) respectively covering the opposite two sides of the first metal current collector (211); The metal negative electrode current collector electrode (22) includes a second metal current collector (221) and two second negative electrode active material layers (222), with the two second negative electrode active material layers (222) respectively covering the opposite two sides of the second metal current collector (221).
9. The battery cell according to claim 8, characterized in that, The thickness of the first metal current collector (211) is 5.8μm-12.2μm, and the thickness of the second metal current collector (221) is 2.8μm-6.2μm.
10. The battery cell according to any one of claims 1-6, characterized in that, The sum of the number of composite current collector electrodes in the first composite current collector electrode section and the number of composite current collector electrodes in the second composite current collector electrode section is A, and the number of metal current collector electrodes is B, wherein 8% ≤ A / (A+B) ≤ 72%.
11. A single battery cell, characterized in that, It includes a housing and a battery cell as described in any one of claims 1-10, wherein the battery cell is disposed within the housing.