Single cell

Abstract

The application relates to a single battery. The single battery comprises a shell, a cover plate assembly, a pole core and a heat conduction piece. The heat conduction piece is arranged in the pole core, and the heat conduction piece is connected to the cover plate assembly and the shell at two ends in a first direction; wherein a plurality of heat exchange holes are arranged on the heat conduction piece and penetrate the heat conduction piece in a second direction. By arranging the heat conduction piece in the pole core, the heat conduction piece is used to timely conduct the heat in the middle part of the pole core to the edge of the pole core, thereby reducing the temperature in the middle part of the pole core and preventing local overheating. The heat in the middle part of the pole core is conducted to the cover plate assembly and the shell through the heat conduction piece, the temperature gradient of the middle part of the pole core and the top of the pole core is reduced, the accuracy of the battery management system in estimating the state of charge and the state of health of the single battery is improved, and thus the charging and discharging strategy is optimized to meet the demand of high-rate charging and discharging.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a single-cell battery. Background Technology

[0002] Lithium-ion batteries have become the preferred power source for consumer electronics, new energy vehicles, and energy storage due to their high specific energy, excellent rate performance, and long cycle life. However, with the continuous expansion of these applications, the demand for charging and discharging lithium-ion batteries under high-rate conditions is increasing.

[0003] On the one hand, this high-rate charging and discharging will cause a lot of heat to be generated inside the battery. If the heat is not dissipated in time and effectively, it will cause local overheating of the electrode core, resulting in damage to the internal structure of the battery, such as melting of the separator or decomposition of the electrode material, which will lead to battery failure, expansion, leakage, or even explosion or fire, affecting the safety, life and performance of the battery.

[0004] On the other hand, current battery management systems (BMS) estimate the battery's state of charge (SOC) and state of health (SOH) by measuring the temperature at the top of the electrode core. The internal materials and structural design of lithium-ion battery electrodes result in a low thermal conductivity in the in-plane direction, preventing heat from being quickly transferred from the center of the electrode core to the edge. This leads to a large temperature gradient between the center and the edge of the electrode core, causing the BMS to be unable to accurately estimate the battery's SOC and SOH, thus causing the charge and discharge strategy to fail. This phenomenon is particularly pronounced under high-rate charging conditions, making it impossible to meet the demand for higher charging rates. Utility Model Content

[0005] This application provides a single-cell battery that solves the problem that the heat generated inside the battery cannot be dissipated in a timely and effective manner, affecting the battery's safety, lifespan, and performance; and that the low thermal conductivity of the electrode core in the in-plane direction makes it impossible to meet the requirements of higher charging rates.

[0006] To achieve the above objectives, this application provides a single-cell battery having intersecting first and second directions. The single-cell battery includes: a housing with an opening; a cover assembly connected to one end of the housing with the opening and closing the opening; an electrode core housed within the housing; and a heat-conducting element disposed within the electrode core. The heat-conducting element is connected to the cover assembly and the housing at its two ends in the first direction, respectively. The heat-conducting element has a plurality of heat exchange holes, which penetrate the heat-conducting element along the second direction.

[0007] In some embodiments, the heat-conducting element is disposed at the center of the electrode core in the second direction.

[0008] In some embodiments, the heat-conducting element is provided with an expansion clearance groove on at least one side in the second direction.

[0009] In some embodiments, the depth of the expansion clearance groove gradually decreases from the center of the expansion clearance groove toward the edge of the expansion clearance groove.

[0010] In some embodiments, the heat-conducting component has a first snap-fit ​​portion on the side away from the opening, and the inner wall of the housing has a second snap-fit ​​portion that snaps into the first snap-fit ​​portion. The first snap-fit ​​portion includes at least one of a snap-fit ​​protrusion and a snap-fit ​​groove.

[0011] In some embodiments, the first snap-fit ​​portion includes a snap-fit ​​groove coated with a magnetic material; the second snap-fit ​​portion includes a snap-fit ​​protrusion with a magnet embedded therein.

[0012] In some embodiments, the thermal conductive element includes a graphite sheet; the single cell also has a third direction intersecting the first direction and the second direction, and the thermal conductivity of the graphite sheet is 1500W / (mk)-2000W / (mk) in the plane formed by the first direction and the third direction.

[0013] In some embodiments, the single cell further includes an insulating film, which is disposed at least between the heat-conducting element and the electrode core.

[0014] In some embodiments, the single cell further includes a thermal pad, the two ends of which are respectively connected to the cover assembly and the thermal conductive element in a first direction.

[0015] In some embodiments, the cover plate assembly includes: a cover plate, a positive terminal, a negative terminal, and an explosion-proof valve. The positive terminal and the negative terminal are respectively disposed at both ends of the cover plate, and the explosion-proof valve is disposed in the middle of the cover plate. The end of the heat-conducting element near the opening is provided with a positive terminal clearance groove, a negative terminal clearance groove, and an explosion-proof valve clearance groove. The positive terminal clearance groove is disposed corresponding to the positive terminal, the negative terminal clearance groove is disposed corresponding to the negative terminal, and the explosion-proof valve clearance groove is disposed corresponding to the explosion-proof valve. The orthogonal projection of the heat-conducting pad on the cover plate is located outside the orthogonal projections of the positive terminal, the negative terminal, and the explosion-proof valve on the cover plate.

[0016] This application incorporates a heat-conducting component within the electrode core. Utilizing the component's exceptionally high thermal conductivity, heat from the center of the electrode core is promptly transferred to its edges, thereby reducing the temperature in the center, preventing localized overheating, improving the temperature uniformity of the individual battery, minimizing electrochemical reaction instability caused by temperature unevenness, enhancing battery safety, and extending battery life.

[0017] This application incorporates a heat-conducting component within the electrode core, with its two ends connected to the cover plate assembly and the housing, respectively. The heat is conducted from the center of the electrode core to the cover plate assembly and the housing via the heat-conducting component, thereby reducing the temperature gradient between the center and top of the electrode core. This improves the accuracy of the battery management system in estimating the state of charge and health of individual cells, thus optimizing the charging and discharging strategy to meet the demands of high-rate charging and discharging.

[0018] The heat-conducting component of this application is provided with heat exchange holes. The heat exchange holes increase the heat exchange area between the heat-conducting component and the electrolyte in the casing, further improving the heat dissipation efficiency of the single cell. This effectively manages the temperature inside the electrode core, helps to improve the charge and discharge efficiency and cycle life of the single cell, helps to reduce the risk of thermal runaway of the single cell, and enhances the safety of the single cell. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0021] Figure 1 This is a schematic diagram of the structure of a single battery provided in an embodiment of this application;

[0022] Figure 2 The explosion of a single cell provided in the embodiments of this application. Figure 1 ;

[0023] Figure 3 The explosion of a single cell provided in the embodiments of this application. Figure 2 ;

[0024] Figure 4 This is a schematic diagram of the structure of the cover plate assembly of a single battery provided in an embodiment of this application;

[0025] Figure 5 This is a partial structural schematic diagram of the electrode core of a single battery provided in an embodiment of this application;

[0026] Figure 6 This is a cross-section of the heat-conducting component of a single-cell battery provided in an embodiment of this application. Figure 1 ;

[0027] Figure 7 This is a cross-sectional view of the casing of a single battery provided in an embodiment of this application;

[0028] Figure 8 This is a cross-section of the heat-conducting component of a single-cell battery provided in an embodiment of this application. Figure 2 ;

[0029] Figure 9 yes Figure 8 Enlarged view of the area within the middle circle;

[0030] Figure 10 This is a top view of the heat-conducting component and insulating film of a single-cell battery provided in an embodiment of this application.

[0031] Explanation of reference numerals in the attached figures:

[0032] M, first direction; N, second direction; P, third direction;

[0033] 1. Housing; 2. Cover plate assembly; 3. Electrode core; 4. Thermal conductive component; 5. Thermal conductive pad; 6. Insulating film;

[0034] 11. Opening; 12. Second snap-fit ​​part;

[0035] 21. Cover plate; 22. Positive terminal; 23. Negative terminal; 24. Explosion-proof valve;

[0036] 31. Positive electrode plate; 32. Negative electrode plate; 33. Separator; 311. Positive electrode tab; 321. Negative electrode tab;

[0037] 41. Positive electrode post clearance groove; 42. Negative electrode post clearance groove; 43. Explosion-proof valve clearance groove; 44. First snap-fit ​​part; 45. Heat exchange hole; 46. Expansion clearance groove;

[0038] 51. First thermal pad; 52. Second thermal pad. Detailed Implementation

[0039] 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 a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0040] Please see Figure 1 This application provides a single-cell battery. The single-cell battery has a first direction M, a second direction N, and a third direction P that intersect each other. In this embodiment, the first direction M, the second direction N, and the third direction P are perpendicular to each other. The perpendicularity of the first direction M, the second direction N, and the third direction P can be understood as the angle between each pair of the first direction M, the second direction N, and the third direction P being 80° to 90°, and is not limited thereto.

[0041] Please refer to the following: Figure 2 and Figure 3 The single cell includes: a casing 1, a cover plate assembly 2, an electrode core 3, and a heat-conducting component 4.

[0042] Please see Figure 3 The housing 1 has an opening 11. The opening 11 allows the electrode core 3 to pass through and be accommodated within the housing 1. In this embodiment, the housing 1 is made of aluminum. Therefore, the housing 1 has advantages such as light weight, good thermal conductivity, and corrosion resistance. In other embodiments, other materials can be selected based on factors such as the application environment, performance requirements, cost, and manufacturing process of the individual battery. Examples include stainless steel, nickel alloys, titanium alloys, ceramic materials, and carbon fiber composite materials.

[0043] Please see Figures 1-4 The cover assembly 2 is connected to one end of the housing 1 that has an opening 11 and closes the opening 11. The cover assembly 2 includes: a cover 21, a positive terminal 22, a negative terminal 23 and an explosion-proof valve 24.

[0044] The cover plate 21 closes the opening 11 and protects the electrode core 3. The cover plate 21 is typically made of metal or other durable materials. In this embodiment, the cover plate 21 is made of aluminum. Therefore, the casing 1 has advantages such as light weight, good thermal conductivity, and corrosion resistance. In other embodiments, other materials can be selected based on factors such as the application environment, performance requirements, cost, and manufacturing process of the individual battery.

[0045] The positive terminal 22 and the negative terminal 23 are respectively located at both ends of the cover plate 21. The positive terminal 22 is electrically connected to the positive tab 311 of the electrode core 3, and the negative terminal 23 is electrically connected to the negative tab 321 of the electrode core 3. The explosion-proof valve 24 is located in the middle of the cover plate 21.

[0046] Among them, the explosion-proof valve 24 is a safety device used to release pressure when the internal pressure of a single cell is too high, so as to prevent the single cell from exploding or being damaged.

[0047] Please see Figure 2 and Figure 5 The electrode core 3 is housed within the housing 1. The electrode core 3 includes a positive electrode 31, a negative electrode 32, and a separator 33, with the separator 33 disposed between the positive electrode 31 and the negative electrode 32. The positive electrode 31 has a positive tab 311 near the opening 11, and the negative electrode 32 has a negative tab 321 near the opening 11. In this embodiment, the electrode core 3 is formed by winding the positive electrode 31, the negative electrode 32, and the separator 33. In other embodiments, the electrode core 3 can be formed by stacking the positive electrode 31, the negative electrode 32, and the separator 33.

[0048] Please see Figure 2A heat-conducting element 4 is disposed within the electrode core 3. In this embodiment, the heat-conducting element 4 is disposed at the center of the electrode core 3 in the second direction N. In other words, the central axis of the heat-conducting element 4 in the second direction N coincides with the central axis of the electrode core 3 in the second direction N. In this embodiment, the heat-conducting element 4 includes a graphite sheet. In the plane formed by the first direction M and the third direction P, the thermal conductivity of the graphite sheet is 1500W / (mk)-2000W / (mk). By disposing of the heat-conducting element 4 within the electrode core 3, the extremely high thermal conductivity of the heat-conducting element 4 is utilized to promptly conduct heat from the center of the electrode core 3 to the edge of the electrode core 3, thereby reducing the temperature in the center of the electrode core 3, preventing local overheating, improving the temperature uniformity of the single cell, reducing electrochemical reaction instability caused by temperature unevenness, enhancing the safety of the single cell, and extending the life of the single cell.

[0049] Please see Figure 2 and Figure 3 The heat-conducting component 4 has a positive electrode post clearance groove 41, a negative electrode post clearance groove 42, and an explosion-proof valve clearance groove 43 at the end near the opening 11. The positive electrode post clearance groove 41 is correspondingly set to the positive electrode post 22. After the electrode core 3 enters the housing 1, the positive electrode post clearance groove 41 is used to avoid welding between the positive electrode tab 311 and the positive electrode post 22. The negative electrode post clearance groove 42 is correspondingly set to the negative electrode post 23. After the electrode core 3 enters the housing 1, the negative electrode post clearance groove 42 is used to avoid welding between the negative electrode tab 321 and the negative electrode post 23. The explosion-proof valve clearance groove 43 is correspondingly set to the explosion-proof valve 24. When the electrode core 3 experiences thermal runaway, the explosion-proof valve clearance groove 43 facilitates the smooth opening and detonation of the explosion-proof valve 24.

[0050] Please see Figure 2 The heat-conducting component 4 is connected to the cover plate assembly 2 and the housing 1 at both ends in the first direction M, respectively. By setting the heat-conducting component 4 inside the electrode core 3, with its two ends connected to the cover plate assembly 2 and the housing 1, the heat in the middle of the electrode core 3 is conducted to the cover plate assembly 2 and the housing 1 through the heat-conducting component 4, reducing the temperature gradient between the middle and top of the electrode core 3, improving the accuracy of the battery management system in estimating the state of charge and health of individual cells, and thus optimizing the charging and discharging strategy to meet the needs of high-rate charging and discharging.

[0051] Please see Figures 2-4In this embodiment, the single battery cell also includes a thermal pad 5. The thermal pad 5 is connected to the cover plate assembly 2 and the thermal conductive element 4 at both ends in the first direction M, respectively. That is, in this embodiment, the thermal conductive element 4 is indirectly connected to the cover plate assembly 2 through the thermal pad 5. Specifically, the material of the thermal pad 5 can be silicone. The thermal pad 5 can be tightly bonded to the surface of the cover plate assembly 2 near the housing 1 by adhesive bonding. When the cover plate assembly 2 is assembled with the housing 1, the surface of the thermal pad 5 away from the cover plate assembly 2 abuts against the surface of the thermal conductive element 4 near the cover plate assembly 2. By providing the thermal pad 5 between the thermal conductive element 4 and the cover plate assembly 2, the thermal conductive element 4 can promptly conduct heat from the middle of the electrode core 3 to the top of the electrode core 3, and then promptly conduct it to the cover plate assembly 2 through the thermal pad 5, improving the heat dissipation efficiency of the electrode core 3. In other embodiments, the thermal pad 5 can be omitted depending on the actual situation; in this case, the thermal conductive element 4 is directly connected to the cover plate assembly 2.

[0052] The thermal pad 5 has a compression rate of 20%-40%. Therefore, when the cover plate assembly 2 is assembled with the housing 1, the size of the thermal pad 5 in the first direction M can be slightly reduced so that the two ends of the thermal pad 5 in the first direction M are tightly attached to the cover plate assembly 2 and the thermal conductive element 4, thereby ensuring the heat exchange stability of the single cell.

[0053] Please see Figure 2 and Figure 3 The orthographic projection of the thermal pad 5 on the cover plate 21 is outside the orthographic projections of the positive electrode 22, the negative electrode 23, and the explosion-proof valve 24 on the cover plate 21. In this embodiment, the thermal pad 5 includes a first thermal pad 51 and a second thermal pad 52. The first thermal pad 51 is correspondingly disposed with the thermal conductive element 4 between the explosion-proof valve clearance groove 43 and the positive electrode clearance groove 41, and the second thermal pad 52 is correspondingly disposed with the thermal conductive element 4 between the explosion-proof valve clearance groove 43 and the negative electrode clearance groove 42.

[0054] Please see Figure 6 and Figure 7 The heat-conducting component 4 has a first engaging portion 44 on the side away from the opening 11, and the inner wall of the housing 1 has a second engaging portion 12 that engages with the first engaging portion 44. The first engaging portion 44 includes at least one of an engaging protrusion and an engaging groove. In this embodiment, the first engaging portion 44 is an engaging groove, and the second engaging portion 12 is an engaging protrusion. When the heat-conducting component 4 enters the housing 1, it engages with the first engaging portion 44 and the second engaging portion 12, thereby improving the connection stability between the heat-conducting component 4 and the housing 1 and improving the accuracy of the installation position of the heat-conducting component 4 within the housing 1.

[0055] In some embodiments, the first snap-fit ​​portion 44 includes a snap-fit ​​groove coated with a magnetic material (not shown), such as the soft magnetic material iron oxide; the second snap-fit ​​portion 12 includes a snap-fit ​​protrusion with a magnet embedded therein (not shown). By coating the snap-fit ​​groove with a magnetic material and embedding a magnet in the snap-fit ​​protrusion, the magnetic attraction between the snap-fit ​​groove and the snap-fit ​​protrusion further improves the connection stability between the heat-conducting component 4 and the housing 1 and the accuracy of the installation position of the heat-conducting component 4.

[0056] Please see Figure 6 The heat-conducting component 4 is provided with multiple heat exchange holes 45, which penetrate the heat-conducting component 4 along the second direction N. By utilizing the heat exchange holes 45, the heat exchange area between the heat-conducting component 4 and the electrolyte inside the casing 1 is increased, further improving the heat dissipation efficiency of the single battery cell. This effectively manages the temperature inside the electrode core 3, helps to improve the charge and discharge efficiency and cycle life of the single battery cell, helps to reduce the risk of thermal runaway of the single battery cell, and enhances the safety of the single battery cell.

[0057] Please see Figure 8 and Figure 9 The heat-conducting component 4 has an expansion relief groove 46 on at least one side in the second direction N. By providing the expansion relief groove 46 on the heat-conducting component 4, the expansion relief groove 46 absorbs the expansion deformation of the center part of the electrode core 3 during the use of the single cell, thereby extending the cycle life of the single cell.

[0058] Please see Figure 9 The depth L1 of the expansion relief groove 46 gradually decreases from the center of the expansion relief groove 46 toward the edge of the expansion relief groove 46. This allows the expansion relief groove 46 to better adapt to the expansion and deformation of the electrode core 3 during the use of the single cell.

[0059] Please see Figure 10 In some embodiments, the single-cell battery further includes an insulating film 6. The insulating film 6 is disposed at least between the heat-conducting element 4 and the electrode core 3. In some embodiments, the insulating film 6 may be formed by coating the heat-conducting element 4 with aluminum oxide. In some embodiments, depending on the actual situation, aluminum oxide may not be coated on the heat-conducting element 4, but may instead be disposed on the surface of the electrode core 3 near the heat-conducting element 4. The insulating film 6 prevents short circuits caused by contact between the heat-conducting element 4 and the positive electrode 31 or negative electrode 32 of the electrode core 3.

[0060] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0061] In the above embodiments, the descriptions of each embodiment have their own emphasis. Parts not described in detail in a particular embodiment can be referred to in the relevant descriptions of other embodiments. The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0062] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A single-cell battery, characterized in that, Having intersecting first direction (M) and second direction (N), the single cell comprises: The shell (1) has an opening (11); A cover plate assembly (2) is connected to one end of the housing (1) having the opening (11) and closes the opening (11); The electrode core (3) is housed within the housing (1); and A heat-conducting component (4) is disposed inside the pole core (3), and the heat-conducting component (4) is connected to the cover plate assembly (2) and the housing (1) at both ends in the first direction (M); The heat-conducting component (4) is provided with a plurality of heat exchange holes (45), which penetrate the heat-conducting component (4) along the second direction (N).

2. The single-cell battery according to claim 1, characterized in that, The heat-conducting element (4) is disposed at the center of the pole core (3) in the second direction (N).

3. The single-cell battery according to claim 1, characterized in that, The heat-conducting component (4) has an expansion relief groove (46) on at least one side of the second direction (N).

4. The single-cell battery according to claim 3, characterized in that, The depth of the expansion clearance groove (46) gradually decreases from the center of the expansion clearance groove (46) toward the edge of the expansion clearance groove (46).

5. The single-cell battery according to claim 1, characterized in that, The heat-conducting component (4) has a first snap-fit ​​portion (44) on the side away from the opening (11), and the inner wall of the housing (1) has a second snap-fit ​​portion (12) that snaps into the first snap-fit ​​portion (44). The first snap-fit ​​portion (44) includes at least one of a snap-fit ​​protrusion and a snap-fit ​​groove.

6. The single-cell battery according to claim 5, characterized in that, The first snap-fit ​​portion (44) includes a snap-fit ​​groove, and the snap-fit ​​groove is coated with a magnetic material; The second snap-fit ​​portion (12) includes a snap-fit ​​protrusion, and a magnet is embedded in the snap-fit ​​protrusion.

7. The single-cell battery according to claim 5, characterized in that, The heat-conducting component (4) includes a graphite sheet; The single cell also has a third direction (P) intersecting the first direction (M) and the second direction (N). In the plane formed by the first direction (M) and the third direction (P), the thermal conductivity of the graphite sheet is 1500W / (mk)-2000W / (mk).

8. The single-cell battery according to claim 1, characterized in that, The single cell also includes an insulating film (6), which is disposed at least between the heat-conducting element (4) and the electrode core (3).

9. The single-cell battery according to claim 1, characterized in that, The single cell also includes a thermal pad (5), which is connected to the cover plate assembly (2) and the thermal conductive element (4) at both ends in the first direction (M).

10. The single-cell battery according to claim 9, characterized in that, The cover plate assembly (2) includes: a cover plate (21), a positive terminal (22), a negative terminal (23), and an explosion-proof valve (24). The positive terminal (22) and the negative terminal (23) are respectively disposed at both ends of the cover plate (21), and the explosion-proof valve (24) is disposed in the middle of the cover plate (21). The heat-conducting component (4) has a positive electrode clearance groove (41), a negative electrode clearance groove (42), and an explosion-proof valve clearance groove (43) at one end near the opening (11). The positive electrode clearance groove (41) is corresponding to the positive electrode (22), the negative electrode clearance groove (42) is corresponding to the negative electrode (23), and the explosion-proof valve clearance groove (43) is corresponding to the explosion-proof valve (24). The orthogonal projection of the heat-conducting pad (5) on the cover plate (21) is outside the orthogonal projections of the positive electrode (22), the negative electrode (23), and the explosion-proof valve (24) on the cover plate (21).

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