Pole piece and battery
By setting a low-melting-point protective layer between the current collector and the tab of the lithium-ion battery, the problem of thermal runaway caused by external short circuits in the battery is solved, thus improving the safety of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-03-24
AI Technical Summary
Lithium-ion batteries are prone to thermal runaway when short-circuited externally, leading to safety hazards.
A protective layer with a melting point lower than that of the current collector and the tab is placed between them. The protective layer melts and disconnects the connection when the temperature reaches its melting point, thus preventing the battery temperature from continuing to rise.
It effectively prevents battery thermal runaway, protects user safety, and avoids fires or explosions.
Smart Images
Figure CN224036598U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to battery technology field especially relates to a pole piece and battery. BACKGROUND
[0002] Lithium ion battery as a kind of efficient energy storage equipment, has been widely used in mobile electronic device, electric vehicle and energy storage system etc. However, the safety performance of lithium ion battery has been one of the key factors restricting its further popularization and application. When lithium ion battery suffers external short circuit, the battery internal electric core will discharge at extremely high rate, not only a large amount of joule heat will be generated in this process, but also reversible chemical reaction heat release. Since the heat generation rate of battery is much greater than its heat dissipation rate, the temperature inside the battery rises rapidly. Once the battery internal temperature exceeds 70 DEG C, a series of side reactions will be triggered, and these side reactions will release more heat, further push up the battery temperature. With the continuous rise of temperature, the separator material inside the battery may be fused due to high temperature, which will lead to the expansion of short circuit area, form more serious short circuit state. This vicious cycle may eventually lead to thermal runaway of battery, that is, the battery temperature continues to rise uncontrollably, until fire or explosion is caused, which poses a serious threat to personal and property safety. SUMMARY
[0003] The utility model embodiment provides a kind of pole piece, lithium ion battery and battery, to solve the problem of battery external short circuit and cause thermal runaway, reach the effect of avoiding user's personal and property safety is threatened.
[0004] Specifically, the utility model provides a kind of pole piece, including current collector, protective layer and tab, the protective layer is set on the current collector, and the tab is welded on the protective layer;The melting point of the protective layer is lower than the melting point of the tab, and lower than the melting point of the current collector.
[0005] Optionally, the thickness h of the protective layer satisfies: 0 μm < h ≤ 20 μm.
[0006] Optionally, 5 μm < h ≤ 15 μm.
[0007] Optionally, the material of the protective layer is one of lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy.
[0008] Optionally, the current collector has a first surface, the first surface includes an empty foil area and a coating area, the protective layer is arranged in the empty foil area, and an active material layer is arranged in the coating area.
[0009] Optionally, the width W3 of the empty foil area is greater than the width W2 of the protective layer, and the width W2 of the protective layer is not less than the width W1 of the tab.
[0010] Optionally, the empty foil area is located at either end of the coating area; or, the empty foil area is located in the middle of the coating area.
[0011] Optionally, the current collector has a second surface, which is located on the opposite side of the first surface, and the second surface is provided with an active material layer.
[0012] Optionally, along the width direction of the current collector, the current collector, the protective layer and the tab are sequentially connected.
[0013] The difference between the area of the projection of the protective layer 200 on the current collector 100 and the area of the projection of the tab 300 on the current collector 100 is S1;
[0014] The area of the empty foil area 110 is S2; 0%≤S1 / S2≤10%.
[0015] Optionally, the tab is a positive electrode tab or a negative electrode tab.
[0016] The utility model further provides a kind of battery, including the tab as any one of the above.
[0017] The utility model has the beneficial effects that:
[0018] The utility model sets up protective layer between current collector and tab, since the melting point of protective layer is lower than the melting point of tab and the melting point of current collector, therefore, when battery external short circuit, protective layer is first affected, and protective layer melts when temperature reaches the melting point of protective layer, so that tab and current collector are disconnected, avoid battery temperature continue to rise, and cause battery to occur thermal runaway phenomenon, to further avoid the threat to personal and property safety of user. BRIEF DESCRIPTION OF DRAWINGS
[0019] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the following will be briefly introduced to the drawings needed to be used in the description of the embodiments of the utility model, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can be obtained according to these drawings without creative labor.
[0020] Figure 1 It is the schematic structural diagram of tab in one embodiment of the utility model;
[0021] Figure 2 It is the schematic structural diagram of tab in another embodiment of the utility model.
[0022] In the drawing: 100, current collector, 110, empty foil area, 120, coating area, 200, protective layer, 300, tab.
[0023] W1, width of the tab, W2, width of the protective layer, W3, width of the empty foil area. DETAILED DESCRIPTION
[0024] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model clearer and more apparent, the utility model will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the utility model and do not limit the utility model.
[0025] In the description of the utility model, it should be understood that the orientation or position relationship indicated by the terms "longitudinal", "radial", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and therefore cannot be understood as a limitation on the utility model. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.
[0026] In the description of the utility model, it should be noted that, unless otherwise specified and limited, the terms "mounting", "connection" and "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be internal glue injection of two elements. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.
[0027] Figure 1 is a schematic structural diagram of a battery assembly in an embodiment of the utility model, as Figure 1 As shown in the utility model embodiment, a tab is provided, which comprises a current collector 100, a protective layer 200 and a tab 300, the protective layer 200 is arranged on the current collector 100, and the tab 300 is welded on the protective layer 200; the melting point of the protective layer 200 is lower than the melting point of the tab 300 and lower than the melting point of the current collector 100.
[0028] In application, if the battery is externally short-circuited, the current will increase sharply, resulting in a large amount of heat generated inside the battery. Since the melting point of the protective layer 200 is low, it will melt first. This process disconnects the connection between the tab 300 and the current collector 100, effectively cutting off the current conduction path inside the battery, and rapidly reducing the heat generation rate inside the battery. This helps to protect other components inside the battery, such as electrolyte and separator, from thermal runaway, thereby avoiding threats to the safety of users and their property.
[0029] That is, the embodiment of the utility model sets the protective layer 200 between the current collector 100 and the tab 300, and since the melting point of the protective layer 200 is lower than that of the tab 300 and the current collector 100, when the battery is externally short-circuited, the protective layer 200 is affected first, and when the temperature reaches the melting point of the protective layer 200, the protective layer 200 melts, disconnecting the tab 300 and the current collector 100, and preventing the battery temperature from continuing to rise.
[0030] In an embodiment of the utility model, the thickness h of the protective layer 200 satisfies: 0 μm < h ≤ 20 μm. Specifically, the thickness h of the protective layer 200 is 0.1 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm or a range between any two values.
[0031] Preferably, 5 μm < h ≤ 15 μm. If the thickness h of the protective layer 200 is too large, it will increase the total thickness of the current collector 100, the protective layer 200 and the tab 300 at the location of the protective layer 200, which not only affects the overall compactness of the battery, but also may reduce the energy density of the battery; if the thickness h of the protective layer 200 is too small, i.e. the protective layer 200 is too thin, the protective layer 200 may be welded through during the welding of the tab 300, causing the tab 300 to be directly welded on the current collector 100, losing the melting breaking function of the protective layer 200.
[0032] In an embodiment of the utility model, the material of the protective layer 200 is one of lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy. Since lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy all have good electrical conductivity and low melting point characteristics, they can quickly melt when the battery is short-circuited, cutting off the circuit and preventing further damage, thereby improving the safety of the battery.
[0033] In an embodiment of the utility model, the current collector 100 has a first surface, the first surface includes the empty foil area 110 and the coating area 120, the protective layer 200 is arranged in the empty foil area 110, and the tab 300 is welded on the protective layer 200; the coating area 120 is provided with an active material layer. Further, the current collector 100 has a second surface, the second surface and the first surface are respectively located on both sides of the current collector 100, and the second surface is provided with an active material layer.
[0034] In the embodiment, the width of the empty foil area 110 is greater than the width of the protective layer 200, so that the edge of the empty foil area 110 is spaced apart from the edge of the active material layer, and thus the protective layer 200 and the tab 300 can be separated from the active material layer of the coating area 120. In this way, the adverse effects of the active material on the welded part of the tab 300 or the protective layer 200 during the charging and discharging of the battery can be avoided, such as chemical corrosion or physical interference (for example, the expansion and contraction of the active material during the charging and discharging process may affect the connection of the tab 300).
[0035] Further, the width W3 of the empty foil area 110 is greater than the width W2 of the protective layer 200, and the width W2 of the protective layer 200 is not less than the width W1 of the tab 300; that is, W1≤W2
[0036] Further, the difference between the area of the projection of the protective layer 200 on the current collector 100 and the area of the projection of the tab 300 on the current collector 100 is S1; the area of the empty foil area 110 is S2; and 0%≤S1 / S2≤10%. Under the premise of limiting W1≤W2, further limiting 0%≤S1 / S2 can ensure that the projection of the tab 300 on the current collector 100 falls completely on the protective layer 200, avoiding the tab 300 from being welded on the current collector 100 during welding. At the same time, limiting S1 / S2≤10% can avoid the area of the protective layer 200 contacting the tab 300 on the current collector 100 being too large, on the one hand avoiding the waste of the protective layer 200, and on the other hand ensuring that there is enough spacing between the protective layer 200 and the active material layer of the coating area 120, avoiding the adverse effects of the active material on the welded part of the tab 300 or the protective layer 200 during the charging and discharging of the battery.
[0037] In one embodiment of this invention, the empty foil area 110 is located at either end of the coating area 120; or, the empty foil area 110 is located in the middle of the coating area 120. This arrangement allows the tab 300 to be welded to the head, middle, or tail of the current collector 100 to adapt to different battery requirements.
[0038] like Figure 2 As shown, in one embodiment of this invention, the current collector 100, the protective layer 200, and the tab 300 are sequentially connected along the width direction of the current collector 100. This avoids increasing the total thickness of the current collector 100, the protective layer 200, and the tab 300 at the location of the protective layer 200, thus preventing any impact on the overall compactness and energy density of the battery. The end of the protective layer 200 near the current collector 100 has the same thickness as the current collector 100; the end of the protective layer 200 near the tab 300 has the same thickness as the tab 300, ensuring alignment accuracy during welding and improving welding quality and reliability.
[0039] In one embodiment of this invention, the electrode is either a positive electrode or a negative electrode. In the same battery, both the positive and / or negative electrode can adopt the electrode structure described in the above embodiments.
[0040] This utility model embodiment also discloses a battery, including the electrode sheet in any of the above embodiments, to have all the effects of the electrode sheet.
[0041] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.
Claims
1. A pole piece, characterized in that, The electrode tab comprises a current collector (100), a protective layer (200) and a tab (300), the protective layer (200) is arranged on the current collector (100), and the tab (300) is welded on the protective layer (200); the melting point of the protective layer (200) is lower than the melting point of the tab (300) and lower than the melting point of the current collector (100).
2. The electrode tab according to claim 1, wherein The thickness h of the protective layer (200) satisfies 0 μm < h ≤ 20 μm.
3. The electrode tab according to claim 1, wherein 5 μm < h ≤ 15 μm.
4. The electrode tab according to claim 1, wherein The material of the protective layer (200) is one of lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy.
5. The electrode tab according to claim 1, wherein The current collector (100) has a first surface, the first surface comprises an empty foil area (110) and a coating area (120), the protective layer (200) is arranged on the empty foil area (110), and an active material layer is arranged in the coating area (120).
6. The electrode tab according to claim 5, wherein The width W3 of the empty foil area (110) is greater than the width W2 of the protective layer (200), and the width W2 of the protective layer (200) is not less than the width W1 of the tab (300).
7. The electrode tab according to claim 5, wherein The empty foil area (110) is located at either end of the coating area (120); or the empty foil area (110) is located in the middle of the coating area (120).
8. The electrode tab according to claim 5, wherein The difference between the area of the projection of the protective layer (200) on the current collector (100) and the area of the projection of the tab (300) on the current collector (100) is S1; the area of the empty foil area (110) is S2; and 0% ≤ S1 / S2 ≤ 10%. The electrode tab is a positive electrode tab or a negative electrode tab.
9. The pole piece according to any one of claims 1 to 8, characterized in that The electrode tab comprises the electrode tab according to any one of claims 1 to 8 or the electrode tab according to claim 9.
10. A battery, characterized by