Thermal runaway prevention pole piece and battery cell unit
By incorporating a thermosensitive conductive coating and a conductive separator into the lithium-ion battery electrodes, the problem of battery thermal runaway was solved, thereby improving battery safety and stabilizing electrical performance.
Patent Information
- Application Number
- CN202423207712.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2034-12-25
AI Technical Summary
Existing technologies cannot effectively suppress thermal runaway inside lithium-ion batteries. Temperature fuses and thermal runaway detection and alarm systems can only react after thermal runaway has occurred, and cannot fundamentally solve the battery safety problem.
A thermosensitive conductive coating and a conductive membrane are placed between the current collector and the electrode material layer. The resistance of the thermosensitive conductive coating changes with temperature, which hinders the current flow and suppresses the battery heating. The conductive membrane isolates the thermosensitive conductive coating from the electrode material to prevent material mixing from affecting the electrical performance.
It effectively suppresses battery thermal runaway, prevents battery overheating, ensures the restoration of normal battery charging and discharging functions, and avoids degradation of electrical performance.
Smart Images
Figure CN223858140U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the battery design manufacturing technical field especially relates to a kind of pole piece and electric core unit of heat runaway prevention. BACKGROUND
[0002] Lithium-ion batteries have become an indispensable energy storage solution in mobile electronic devices, electric vehicles and energy storage systems due to their high energy density, long life and good charging performance. However, as industrial progress increases the demand for longer cycle life, higher energy density and cost-effectiveness, the safety of lithium-ion batteries has become increasingly prominent. During the misuse of the battery, problems such as thermal runaway (TR), external impact, overcharging and overdischarging may occur, which can accelerate the chemical reaction inside the battery and generate a large amount of heat energy, leading to a fire or even an explosion.
[0003] Among them, in the face of battery thermal runaway problem, the prior art has developed technologies such as setting temperature fuse on current path, designing overcharge protection circuit on battery, and setting thermal runaway detection alarm system on battery to improve battery safety and reduce the probability of battery thermal runaway.
[0004] However, since the area where the battery thermal runaway occurs is mainly in the battery core, the temperature fuse cannot be set inside the core, and the battery does not only overheat during charging and discharging, let alone the thermal runaway detection alarm system can only detect after the battery overheats. The above technical means cannot fundamentally suppress or solve the battery thermal runaway problem. SUMMARY
[0005] The utility model provides a kind of pole piece and electric core unit of heat runaway prevention, heat-sensitive conductive coating is provided between current collector and electrode material, when battery temperature rises, the resistance of heat-sensitive conductive coating rises to hinder normal charging and discharging of battery, so as to inhibit battery temperature rise, when battery temperature drops, the resistance of heat-sensitive conductive coating reduces, so that battery gradually recovers normal charging and discharging;And electrode material and heat-sensitive conductive coating are also spaced apart by first diaphragm, first diaphragm is conductive diaphragm, which can prevent the mixing of materials in heat-sensitive conductive coating and electrode material to reduce battery electrical performance, to effectively prevent battery thermal runaway, and further solve the above technical problems.
[0006] The technical solution of the utility model to solve the above problems is to provide a kind of pole piece of heat runaway prevention, the pole piece includes current collector, electrode material layer, heat-sensitive conductive coating, the resistance value of heat-sensitive conductive coating increases with the rise of temperature, heat-sensitive conductive coating is completely spaced apart between current collector and electrode material layer, and conductive first diaphragm is further provided between heat-sensitive conductive coating and electrode material layer.
[0007] Furthermore, the sum of the width of one of the current collectors and the thickness of the two thermosensitive conductive coatings is less than the width of the first diaphragm.
[0008] Furthermore, along the width direction of the current collector, adhesive areas are provided at both ends of the first diaphragm.
[0009] Furthermore, the bonding area is configured as a strip-shaped region extending along the length direction of the current collector.
[0010] Furthermore, the bonding area is configured as a plurality of rectangular regions equidistantly distributed along the length direction of the current collector.
[0011] Furthermore, along the width direction of the current collector, both ends of the first diaphragm are provided with conforming edge strips to prevent the edges of the first diaphragm from rolling up.
[0012] Furthermore, the thickness of the thermosensitive conductive coating is between 0.1 μm and 2.0 μm.
[0013] Furthermore, the first diaphragm is a PE conductive film.
[0014] This utility model also provides a battery cell unit, the battery cell unit including a negative electrode sheet, a second separator, and a positive electrode sheet, characterized in that the positive electrode sheet and / or the negative electrode sheet are any of the electrodes mentioned above, and the second separator is disposed between the negative electrode sheet and the positive electrode sheet.
[0015] Furthermore, the second diaphragm is a PE conductive film.
[0016] The beneficial effects of this utility model are:
[0017] 1. A thermistor-conductive coating is provided between the current collector and the electrode material layer. The resistance of the thermistor-conductive coating increases with the increase of temperature. When the internal temperature of the battery rises above the safe temperature threshold, the resistance of the thermistor-conductive coating will increase accordingly, which will cause the charging and discharging power of the battery with this electrode to gradually decrease, or even cause the battery to "open circuit" from the inside, thereby suppressing the battery heating. When the battery temperature drops, the resistance of the thermistor-conductive coating will decrease accordingly, so that the charging and discharging power of the battery after the temperature drops will gradually increase again, and the battery will return to normal operation.
[0018] 2. The thermosensitive conductive coating is covered by the first diaphragm to isolate it from the electrode material layer, so as to effectively prevent the thermosensitive conductive material in the thermosensitive conductive coating from mixing with the active material in the electrode material layer at the boundary between the thermosensitive conductive coating and the electrode material layer, thereby avoiding the thermosensitive conductive coating from hindering the current flow and also preventing the electrical performance of the electrode material layer from deteriorating.
[0019] 3. The first diaphragm also extends to both sides of the heat-sensitive conductive coating in the width direction to further isolate the two side ends of the heat-sensitive conductive coating to avoid the heat-sensitive conductive coating overflowing from both sides of the current collector in the width direction, ensuring that the heat-sensitive conductive coating does not deteriorate in impeding current flow when the temperature rises. BRIEF DESCRIPTION OF DRAWINGS
[0020] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present application and, together with the description, serve to explain the principles of the present application. In the drawings, like reference numerals are used to indicate like elements throughout the various figures. The drawings for the following detailed description are some embodiments of the present application, not all embodiments. For those skilled in the art, other drawings can be obtained from these drawings without creative labor.
[0021] Figure 1 is a structural diagram of the pole piece of the present embodiment;
[0022] Figure 2 is an expanded view of the first diaphragm of the present embodiment;
[0023] Figure 3 is a structural diagram of the battery cell unit of the present embodiment;
[0024] 11 - current collector, 12 - electrode material layer, 13 - heat-sensitive conductive coating, 14 - first diaphragm, 141 - bonding area, 142 - conforming edge strip;
[0025] 21 - negative pole piece, 22 - second diaphragm, 23 - positive pole piece. DETAILED DESCRIPTION
[0026] In the present specification, the orientation terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or possibly mentioned are defined with respect to the structure shown in the drawings, and the words "inner" and "outer" refer to the direction towards or away from the geometric center of a particular component, which are relative concepts, so they can change accordingly according to their different positions, different use states. Therefore, these or other orientation terms should not be interpreted as restrictive terms.
[0027] Please refer to Figure 1 and Figure 2 The pole piece of the present embodiment for preventing thermal runaway includes a current collector 11, an electrode material layer 12, and a heat-sensitive conductive coating 13 (also referred to as a thermistor coating). The heat-sensitive conductive coating 13 is a coating formed by a positive temperature coefficient heat-sensitive conductive material whose resistance increases with temperature rise. The heat-sensitive conductive coating 13 is coated on one side surface of the current collector 11 and is completely spaced between the current collector 11 and the electrode material layer 12.
[0028] To this end, when the above-mentioned tab is applied to a battery cell or even a battery, and the tab gradually heats up during the charging and discharging of the battery, the resistance of the thermally sensitive conductive coating 13 will increase with the increase of temperature, so as to form a surface layer structure with a higher resistance value in the tab, thereby hindering the flow of current in the tab, weakening the charging and discharging power of the battery, and further inhibiting the heating of the battery with the tab, so as to solve the problem of thermal runaway.
[0029] Moreover, when the problem of thermal runaway of the battery is inhibited, the temperature of the battery gradually decreases, and the resistance of the thermally sensitive conductive coating 13 will decrease with the decrease of temperature, so that the current in the tab gradually recovers normal flow, and the charging and discharging power of the battery with the above-mentioned tab gradually recovers normal, so as to gradually restore the normal function of the battery.
[0030] In addition, in the manufacture of the above-mentioned tab, in order to prevent the thermally sensitive conductive material from mixing with the electrode material during the preparation of the tab, causing the resistance of the thermally sensitive conductive coating 13 to deteriorate, and causing the electrical properties of the tab to deteriorate, a first diaphragm 14 is further arranged between the thermally sensitive conductive coating 13 and the electrode material layer 12. The first diaphragm 14 is a pe conductive film, and the first diaphragm 14 is used to physically separate the thermally sensitive conductive coating 13 and the electrode material layer 12, so as to form a clear boundary between the thermally sensitive conductive coating 13 and the electrode material layer 12, thereby preventing the thermally sensitive conductive material from mixing with the electrode material at the interface between the thermally sensitive conductive coating 13 and the electrode material coating.
[0031] In some embodiments, through repeated experiments, the thickness of the thermally sensitive conductive coating 13 is 1 μm, so that when the temperature changes, the thermally sensitive conductive coating 13 is sensitive enough, that is, the resistance change of the thermally sensitive conductive coating 13 responds quickly, and the 1 μm thick thermally sensitive conductive coating 13 will not affect the overall thickness and electrical properties of the tab.
[0032] It should be noted that in other embodiments, the thickness of the thermally sensitive conductive coating 13 can be between 0.1 μm and 2 μm, and it is not limited to 1 μm.
[0033] In some embodiments, the thermally sensitive conductive coating 13 is arranged on the surface of the electrode material layer 12. Figure 1 For example, in the orientation shown in FIG. 1, the front-to-back direction of the current collector 11 is the width direction of the current collector 11. Figure 1 In order to prevent the thermally sensitive conductive coating 13 from being separated from the electrode material layer 12, the first diaphragm 14 is arranged on the surface of the electrode material layer 12. Figure 1The material overflows from both ends of the electrode, affecting the entire electrode. The sum of the width of the current collector 11 and the thickness of the two thermistor conductive coatings 13 is less than the width of the first diaphragm 14. Furthermore, the first diaphragm 14 has an adhesive area 141 at its front and rear ends. Thus, when the first diaphragm 14 is placed between the thermistor conductive coating 13 and the electrode material layer 12, the technician can further move the exposed portion of the first diaphragm 14 on the outside of the front and rear ends of the electrode towards the current collector 11, and use the adhesive area 141 to adhere the front and rear ends of the first diaphragm 14 to the front and rear ends of the current collector 11, so that the first diaphragm 14 further covers the front and rear ends of the thermistor conductive coating 13, so as to avoid the electrical performance of the thermistor conductive coating 13 deteriorating due to the overflow of the thermistor conductive material from the front and rear ends of the electrode.
[0034] In some embodiments, such as Figure 2 As shown, with Figure 2 The left and right directions are the length directions of the current collector 11. The bonding area 141 is a strip-shaped area extending along the length direction of the current collector 11. The bonding area 141 is located on the side of the first diaphragm 14 that contacts the thermosensitive conductive coating 13.
[0035] It should be noted that, although not shown in the embodiments of this application, in other embodiments, the bonding area 141 may also be configured as a plurality of rectangular areas equidistantly distributed along the length direction of the current collector 11.
[0036] In some embodiments, please refer to Figure 1 and Figure 2 ,refer to Figure 1 In the orientation shown, to prevent the first diaphragm 14 from curling, along the width direction of the current collector 11, i.e. Figure 1 In the front and rear end directions, the front and rear ends of the first diaphragm 14 are provided with conforming edge strips 142. The conforming edge strips 142 are made of rigid plastic and are semi-cylindrical strips with their outer circumferential surface exposed.
[0037] Please see Figure 3 The specific embodiments of this utility model also include a battery cell unit, including a negative electrode 21, a second separator 22, and a positive electrode 23. The negative electrode 21 is a type of electrode in the above embodiments that is protected against thermal runaway. The positive electrode 23 is an electrode with a normal structure. The second separator 22 is a PE conductive film. The second separator 22 is physically isolated between the positive electrode 23 and the negative electrode 21. The positive electrode 23 includes a positive current collector and a positive electrode material layer. The positive current collector is aluminum foil, and the positive electrode material layer is made of a positive electrode active material. The negative electrode 21 includes a negative current collector, a thermosensitive conductive coating 13, a first separator 14, and a negative electrode material layer. The negative current collector is copper foil, and the negative electrode material layer is made of a negative electrode active material.
[0038] In the battery containing the above-mentioned battery cell, if the temperature in the battery rises above the safety temperature threshold, the heat-sensitive conductive coating 13 in the negative electrode tab 21 can normally function to reduce the charging and discharging power of the entire battery cell, so as to inhibit the temperature rise of the battery and prevent the thermal runaway of the battery.
[0039] It should be noted that in other embodiments, the positive electrode tab 23 can also adopt one of the above-mentioned heat runaway prevention tabs; or the positive electrode tab 23 is the above-mentioned heat runaway prevention tab, and the negative electrode tab 21 is a conventional tab on the market.
[0040] The above-mentioned matters not mentioned are applicable to the prior art.
[0041] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it. 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.
Claims
1. A pole piece that prevents thermal runaway, characterized by, The pole piece comprises a current collector (11), an electrode material layer (12), and a thermosensitive conductive coating layer (13) whose resistance value increases with temperature rise, the thermosensitive conductive coating layer (13) being completely and separately arranged between the current collector (11) and the electrode material layer (12), and a conductive first diaphragm (14) being further arranged between the thermosensitive conductive coating layer (13) and the electrode material layer (12).
2. The pole piece of claim 1, wherein The sum of the width value of one current collector (11) and the thickness value of two thermosensitive conductive coating layers (13) is less than the width value of the first diaphragm (14).
3. The pole piece of claim 1, wherein Both ends of the first diaphragm (14) are provided with an adhesive area (141) along the width direction of the current collector (11).
4. The pole piece of claim 3, wherein The adhesive area (141) is arranged as a strip-shaped area extending along the length direction of the current collector (11).
5. The pole piece of claim 3, wherein The adhesive area (141) is arranged as a plurality of rectangular areas equidistantly distributed along the length direction of the current collector (11).
6. The pole piece of claim 1, wherein Both end edges of the first diaphragm (14) are provided with a close-fitting edge strip (142) for preventing the edge of the first diaphragm (14) from rolling up along the width direction of the current collector (11).
7. The pole piece of claim 1, wherein The thickness of the thermosensitive conductive coating layer (13) is between 0.1 μm and 2.0 μm.
8. The pole piece of claim 1, wherein The first diaphragm (14) is a pe conductive film.
9. An electric cell unit comprising a negative electrode sheet (21), a second separator (22), and a positive electrode sheet (23), characterized by The positive pole piece (23) and / or the negative pole piece (21) is the pole piece according to any one of claims 1-8, and the second diaphragm (22) is arranged between the negative pole piece (21) and the positive pole piece (23).
10. The cell unit of claim 9, wherein, The second diaphragm (22) is a pe conductive film.