Pole piece and battery
By setting low-melting-point metal components in the empty foil area of the electrode, the problem of thermal runaway caused by external short circuits in lithium-ion batteries is solved, thereby improving battery safety and avoiding the risks of thermal runaway and explosion.
Patent Information
- Application Number
- CN202423214704.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-02-06
- Estimated Expiration
- 2034-12-25
AI Technical Summary
Lithium-ion batteries are prone to thermal runaway when short-circuited externally, leading to safety hazards. Existing technologies are unable to effectively prevent excessive battery temperature rise and explosion.
A low-melting-point metal component is placed in the unconnected area of the electrode foil, where the electrode tab is not connected. The melting point is lower than that of the electrode tab and other parts of the current collector, forming an open circuit to interrupt the electrochemical reaction and prevent the temperature from rising further.
It effectively prevents battery thermal runaway, protects user safety, and avoids excessive battery temperature rise and explosion.
Smart Images
Figure CN223884595U_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 and other fields. 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 far 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 can 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, active material layer and tab, the active material layer is arranged on at least one side of the current collector, the current collector is further provided with the empty foil area, the tab is connected on the empty foil area;The melting point of the part of the empty foil area not connected with the tab is less than the melting point of the tab, and less than the melting point of the rest of the current collector.
[0005] Optionally, a plurality of through holes are provided on the empty foil area, and the plurality of through holes are arranged around the tab;Low-melting-point metal piece is embedded in the through hole.
[0006] Optionally, the part of the empty foil area not connected with the tab is sheet-shaped low-melting-point metal piece.
[0007] Optionally, a recess is provided on the empty foil area, the recess is located between the tab and the active material layer, and is arranged around the tab;Low-melting-point metal piece is embedded in the recess.
[0008] Optionally, the material of the low-melting-point metal piece is one of lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy.
[0009] Optionally, the sum of cross-sectional areas of the plurality of through holes is S1, and the area of the part of the empty foil area not connected with the tab is S2, and 10%≤S1 / S2≤90%.
[0010] Optionally, 30%≤S1 / S2≤70%.
[0011] Optionally, the empty foil area is located at any end of the current collector, or the empty foil area is located at the middle part of the current collector.
[0012] Optionally, the tab is a positive electrode tab or a negative electrode tab.
[0013] The utility model also provides a kind of battery, including the tab as any one of the above.
[0014] The utility model has the beneficial effect that:
[0015] The utility model sets the melting point of the part of the empty foil area not connected with the tab to be less than the melting point of the tab, and less than the melting point of the rest of the current collector, when the battery is externally short-circuited, the part will be affected first. When the temperature reaches its melting point, the part of the empty foil area not connected with the tab will melt, causing the connection between the tab and the active material layer to break, thereby interrupting the electrochemical reaction and preventing the battery temperature from rising further. BRIEF DESCRIPTION OF DRAWINGS
[0016] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the following will be briefly introduced the drawings needed to be used in the description of the embodiments of the utility model, 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.
[0017] Figure 1 is the schematic structural diagram of the tab in an embodiment of the utility model;
[0018] Figure 2 is the schematic structural diagram of the tab in another embodiment of the utility model;
[0019] Figure 3 is the schematic sectional view of the tab in an embodiment of the utility model.
[0020] In the figure: 100, current collector, 110, empty foil area, 111, through hole, 200, active material layer, 300, tab. DETAILED DESCRIPTION
[0021] In order to make the technical problems, technical schemes 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 embodiments. It should be understood that the specific embodiments described herein are only used to explain the utility model and not to limit the utility model.
[0022] 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 does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, 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.
[0023] In the description of the utility model, it should be pointed out that, unless otherwise specified and limited, the terms "mounting", "connection", "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, or it can be internal glue injection of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.
[0024] Figure 1 is a schematic structural diagram of a battery assembly in an embodiment of the utility model, as shown in Figure 1 , and with reference to Figures 2-3 , the utility model embodiment provides a pole piece, which comprises a current collector 100, an active material layer 200 and a tab 300, the active material layer 200 is arranged on at least one side of the current collector 100, the current collector 100 is further provided with an empty foil area 110, and the tab 300 is connected to the empty foil area 110; the melting point of the part of the empty foil area 110 not connected to the tab 300 is less than the melting point of the tab 300 and less than the melting point of the rest of the current collector 100.
[0025] 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 part of the empty foil area 110 not connected to the tab 300 is lower, 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, separator, etc., from thermal runaway, thereby avoiding threats to the safety of the user's person and property.
[0026] That is, the melting point of the part of the empty foil area 110 not connected to the tab 300 is set to be less than the melting point of the tab 300, and less than the melting point of the rest of the current collector 100. When the battery is externally short-circuited, this part will be affected first. When the temperature reaches its melting point, the part of the empty foil area 110 not connected to the tab 300 will melt, causing the connection between the tab 300 and the active material layer 200 to be disconnected, thereby interrupting the electrochemical reaction and preventing the battery temperature from rising further.
[0027] As shown in Figure 1 , Figure 2 In an embodiment of the present application, the part of the empty foil area 110 not connected to the tab 300 is a sheet-shaped low-melting-point metal piece. The low-melting-point metal piece can melt first when a large amount of heat is generated inside the battery, causing the welding portion 110 and the coating portion 120 to be disconnected, thereby preventing the battery temperature from continuing to rise.
[0028] As shown in Figure 2 , Figure 3 In an alternative embodiment of the present application, a plurality of through holes 111 are provided on the empty foil area 110, and the plurality of through holes 111 are arranged around the tab 300; a low-melting-point metal piece is embedded in the through hole 111. The low-melting-point metal piece can melt first when a large amount of heat is generated inside the battery, causing the tab 300 and the active material layer 200 to be connected only through the part between adjacent through holes 111, i.e. reducing the connected area of the part, causing the temperature of the part to rise sharply and melt, thereby disconnecting the connection between the tab 300 and the active material layer 200. This embodiment is divided into two melting processes, and then short-circuited. Compared with the previous embodiment, it has the following advantages: if the low-melting-point metal piece melts after the battery is externally short-circuited, the tab 300 and the active material layer 200 are not disconnected, and the battery can still be used; and this arrangement makes the mechanical strength of the current collector 100 higher than that of the current collector in the previous embodiment.
[0029] Similarly, in the alternative embodiment of the utility model, the hollow foil area 110 is provided with a groove, the groove is located between the tab 300 and the active material layer 200, and is arranged around the tab 300;The low-melting metal piece is embedded in the groove. In this way, the low-melting metal piece can melt first when a large amount of heat is generated inside the battery, so that the tab 300 and the active material layer 200 are connected only by the groove bottom part, that is, the connection area between the tab 300 and the active material layer 200 is reduced, the temperature of the groove bottom part rises sharply and melts, and further the connection between the tab 300 and the active material layer 200 is disconnected.
[0030] The material of the low-melting metal piece in each of the above embodiments 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, cut off the circuit, prevent further damage, and improve the safety of the battery.
[0031] In an embodiment of the utility model, the sum of the cross-sectional areas of the plurality of through holes 111 is S1, the area of the part of the hollow foil area 110 not connected to the tab 300 is S2, and 10%≤S1 / S2≤90%. Specifically, S1 / S2 can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%.
[0032] Preferably, 30%≤S1 / S2≤70%. If S1 / S2 is too small, the area available for setting the low-melting metal piece is relatively small, which not only affects the effect of the low-melting metal piece melting and breaking the circuit, but also makes the spacing between the tab 300 and the active material layer 200 too small, which easily connects the tab 300 to the current collector under the active material layer 200, and makes the low-melting metal piece lose its proper melting and breaking circuit function.
[0033] In an embodiment of the utility model, the hollow foil area 110 is located at either end of the current collector 100;Or, the hollow foil area 110 is located in the middle of the current collector 100. In this way, the tab 300 can be welded at the head, anywhere in the middle or the tail of the current collector 100 to adapt to different needs of the battery.
[0034] In an embodiment of the utility model, the tab is a positive tab or a negative tab. In the same battery, the positive tab and / or the negative tab can adopt the structure of the tab in the above embodiments.
[0035] The utility model embodiment further discloses a battery comprising the tab in any of the above embodiments to have all the effects of the tab.
[0036] The above-described embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.
Claims
1. A pole piece, characterized in that, The electrode tab comprises a current collector (100), an active material layer (200) and a tab (300), the active material layer (200) is arranged on at least one side of the current collector (100), the current collector (100) is further provided with an empty foil area (110), the tab (300) is connected to the empty foil area (110); the melting point of the part of the empty foil area (110) where the tab (300) is not connected is less than the melting point of the tab (300) and the melting point of the rest of the current collector (100).
2. The electrode tab according to claim 1, wherein a plurality of through holes (111) are arranged on the empty foil area (110), and the plurality of through holes (111) are arranged around the tab (300); a low-melting-point metal piece is arranged in the through hole (111).
3. The electrode tab according to claim 1, wherein the low-melting-point metal piece in the part of the empty foil area (110) where the tab (300) is not connected is a sheet-shaped low-melting-point metal piece.
4. The electrode tab according to claim 1, wherein a groove is arranged on the empty foil area (110), the groove is located between the tab (300) and the active material layer (200), and the groove is arranged around the tab (300); a low-melting-point metal piece is arranged in the groove.
5. The electrode tab according to claim 2, wherein the material of the low-melting-point metal piece is one of lead-tin alloy, silver-copper alloy, bismuth alloy and aluminum alloy.
6. The electrode tab according to claim 2, wherein the sum of the cross-sectional areas of the plurality of through holes (111) is S1, the area of the part of the empty foil area (110) where the tab (300) is not connected is S2, and 10%≤S1 / S2≤90%.
7. The electrode tab according to claim 6, wherein 30%≤S1 / S2≤70%.
8. The electrode tab according to claim 1, wherein the empty foil area (110) is located at either end of the current collector (100); or the empty foil area (110) is located in the middle of the current collector (100).
9. The pole piece according to any one of claims 1 to 8, characterized in that The electrode tab is a positive electrode tab or a negative electrode tab.
10. A battery, characterized by The electrode tab comprises the electrode tab according to any one of claims 1 to 8 or the electrode tab according to claim 9.