Batteries, battery packs and electrical devices

Abstract

This application provides a battery, a battery pack, and an electrical device. The battery of this application includes a cell pack and a buffer assembly. The buffer assembly is sandwiched between two adjacent cell packs. The cell pack includes a buffer section and a liquid storage section. The liquid storage section can break and release electrolyte when the cell pack reaches its expansion limit. On the one hand, it can provide a certain expansion space for cell expansion, and on the other hand, it can replenish electrolyte, avoid lithium plating due to insufficient electrolyte, and improve battery safety.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery, a battery pack, and an electrical device. Background Technology

[0002] Lithium-ion power batteries can swell during use, affecting battery life and potentially causing damage to the module frame if the swelling exceeds its allowable limits, leading to safety incidents. Related technologies use buffer materials between cells to absorb battery expansion; however, with increasing cycle counts, insufficient electrolyte can lead to lithium plating. The deposited lithium dendrites may penetrate the separator, causing internal short circuits and compromising battery safety. Utility Model Content

[0003] Embodiments of this application provide a battery, a battery pack, and an electrical device that can improve the technical problem of insufficient electrolyte after an increase in the number of battery cycles.

[0004] In a first aspect, embodiments of this application provide a battery, the battery comprising:

[0005] shell;

[0006] Multiple core packages are installed inside a housing and spaced apart.

[0007] A buffer component, the buffer component comprising:

[0008] A buffer section is sandwiched between two adjacent core packages;

[0009] The liquid storage section is disposed within the buffer section. The liquid storage section includes a first housing and an electrolyte. The electrolyte is disposed within the first housing. The first housing can rupture and release the electrolyte when the core package expands to a preset state.

[0010] In some embodiments, the buffer portion includes a second housing and a buffer material, the buffer material being filled within the second housing and covering the liquid reservoir.

[0011] In some embodiments, along a first direction, the first housing includes two first side plates disposed opposite to each other, the second housing includes two second side plates disposed opposite to each other, the buffer distance between adjacent first side plates and second side plates is D1, each end of each core package is provided with an electrode thinning area, the width of each electrode thinning area is M, and the buffer distance D1 and the width M of the electrode thinning area are equal.

[0012] In some embodiments, the buffer distance D1 is between 10mm and 30mm.

[0013] In some embodiments, along the second direction, the first housing includes two third side plates disposed opposite to each other along the second direction, and each end of the third side plate is connected to a first side plate. The second housing includes two fourth side plates disposed opposite to each other along the second direction, and each end of the fourth side plate is connected to a second side plate. The buffer distance between adjacent third and fourth side plates is D2, which is between 10mm and 30mm. The first direction and the second direction are different.

[0014] In some embodiments, along a third direction, the thickness D3 of the buffer portion is between 3 μm and 5 μm, and / or;

[0015] Along the third direction, the thickness D4 of the liquid storage section is between 1 μm and 2 μm;

[0016] The third direction is different from the first and second directions.

[0017] In some embodiments, the hardness of the first housing is between Shore A 20HA and 40HA, and / or;

[0018] The hardness of the second shell is between 80HA and 100HA on the Shore A scale.

[0019] In some embodiments, the ratio of the length L1 of the buffer assembly to the length L2 of the core package is between 1.01 and 1.03, and / or;

[0020] The ratio of the height H1 of the buffer assembly to the height H2 of the core package is between 1.01 and 1.03.

[0021] In some embodiments, the ratio of the length L1 of the buffer assembly to the length L3 of the outer shell is between 0.96 and 0.98, and / or;

[0022] The ratio of the height H1 of the buffer assembly to the height H3 of the outer shell is between 0.92 and 0.95.

[0023] In some embodiments, the ratio of the volume of the buffer section to the volume of the liquid storage section is between 0.10 and 0.12.

[0024] Secondly, this application also provides a battery pack, including the battery as described above.

[0025] Thirdly, this application also provides an electrical device, including the battery pack as described above.

[0026] The beneficial effects of the embodiments of this application are as follows:

[0027] This application provides a battery, a battery pack, and an electrical device. The battery of this application includes a cell pack and a buffer assembly. The buffer assembly is sandwiched between two adjacent cell packs. The buffer assembly includes a buffer section and a liquid storage section. The liquid storage section can break and release electrolyte when the cell pack reaches its expansion limit. On the one hand, it can provide a certain expansion space for cell expansion, and on the other hand, it can replenish electrolyte to avoid lithium plating due to insufficient electrolyte, thereby improving battery safety performance. Attached Figure Description

[0028] 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 accompanying 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.

[0029] Figure 1 This is a front view of the battery provided in the embodiments of this application. Figure 1 ;

[0030] Figure 2 This is a front view of the battery provided in the embodiments of this application. Figure 2 ;

[0031] Figure 3 This is a top view of the battery provided in an embodiment of this application. Figure 1 ;

[0032] Figure 4 This is a top view of the battery provided in an embodiment of this application. Figure 2 ;

[0033] Figure 5 This is a side view of the battery provided in an embodiment of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100. Battery;

[0036] 10. Outer casing;

[0037] 20. Core packaging;

[0038] 30. Buffer assembly; 31. Liquid reservoir; 311. First housing; 3111. First side plate; 3112. Third side plate; 32. Buffer section; 321. Second housing; 3211. Second side plate; 3212. Fourth side plate;

[0039] 40. Electrode thinning zone. Detailed Implementation

[0040] The technical solutions in 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. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0041] See Figure 1 This application provides a battery 100, which includes a casing 10, a plurality of core packs 20, and a buffer assembly 30. The plurality of core packs 20 are installed inside the casing 10 and are arranged at intervals. The buffer assembly 30 includes a buffer section 32 and a liquid storage section 31. The buffer section 32 is sandwiched between two adjacent core packs 20. The liquid storage section 31 is disposed inside the buffer section 32. The liquid storage section 31 includes a first housing 311 and an electrolyte. The electrolyte is disposed inside the first housing 311. The first housing 311 is capable of breaking and releasing the electrolyte when the core pack 20 reaches its expansion limit.

[0042] In related technologies, a buffer material is added between the core packs to absorb the expansion of the battery 100. However, as the number of cycles increases, insufficient electrolyte can lead to lithium plating. The deposited lithium dendrites may penetrate the separator, causing a short circuit inside the battery 100 and affecting its safety. This application provides a liquid storage section 31 within the buffer assembly 30. The liquid storage section 31 includes a first housing 311 and electrolyte. The electrolyte is disposed within the first housing 311. The first housing 311 can break and release the electrolyte when the core pack 20 expands to a preset state. This provides expansion space for the cell expansion and replenishes electrolyte, preventing lithium plating due to insufficient electrolyte and improving the safety of the battery 100.

[0043] In some embodiments, since the maximum stress and maximum expansion force of the battery cell are positively correlated, if the maximum expansion force of the core pack 20 is 1000 kgf, when the expansion force corresponding to the stress on the core pack 20 is less than or equal to 1000 kgf, the electrolyte in the middle of the storage section 31 flows to the surrounding areas. This effectively alleviates the stress in the middle of the core pack and ensures the flatness of the electrode surface, resulting in uniform stress distribution and reducing the risk of lithium plating caused by uneven stress. When the stress continues to increase, and the expansion force corresponding to the stress on the core pack exceeds 1000 kgf, the core pack 20 expands to a preset state, the structure of the storage section 31 breaks, and the electrolyte is released. Furthermore, the preset state can be when the expansion force corresponding to the stress on the core pack 20 exceeds 80%, 70%, 60%, etc., of the maximum expansion force, or it can be a preset stress value; this is not limited here.

[0044] Please refer to Table 1, which compares battery expansion force and capacity retention. It can be seen that, under the same 100 cycles, the battery with the buffer component 30 has a maximum expansion force of 427 kgf, while the battery without the buffer component 30 has a maximum expansion force of 685 kgf. Under the same 1000 cycles, the battery with the buffer component 30 has a maximum expansion force of 856 kgf, while the battery without the buffer component 30 has a maximum expansion force of 1238 kgf. Excessive battery expansion force will decrease battery cycle performance and may lead to battery rupture, affecting battery safety. Batteries with buffer components can effectively reduce expansion under the same number of cycles.

[0045] Under the same 100-cycle condition, the battery with the buffer component retains 99.3% of its capacity, while the battery without the buffer component retains 96.5%. Under the same 1000-cycle condition, the battery with the buffer component retains 87.5% of its capacity, while the battery without the buffer component retains 83.1%. A higher battery capacity retention rate means slower battery degradation, longer lifespan, and more stable performance. The battery with the buffer component (30) exhibits a higher capacity retention rate under the same cycle number.

[0046] Table 1

[0047]

[0048] In some embodiments, the buffer portion 32 includes a second housing 321 and a buffer material, the buffer material being filled inside the second housing 321 and covering the liquid storage portion 31.

[0049] In some cases, water can be used as the buffer material. As a fluid, water can serve as a medium for energy absorption and shock mitigation. Due to its high specific heat capacity, water absorbs a large amount of heat while its own temperature change is relatively small, making it an ideal material for controlling battery cell temperature. During application, water can absorb the heat released by the battery cell, preventing the cell temperature from becoming too high and thus avoiding performance degradation and safety hazards caused by elevated temperatures. Furthermore, the use of water as a buffer material has the advantages of low cost and easy availability, further enhancing its practicality and economy in battery cell temperature management.

[0050] In some cases, the cushioning material can be a solid structure such as cushioning cotton or cushioning foam, and this application does not limit it.

[0051] In some embodiments, the first housing 311 and the second housing 321 are made of Teflon. Teflon has strong chemical stability, which can ensure the stable performance of the battery 100 during charging and discharging, reduce the risk of failure, and improve safety. The first housing 311 and the second housing 321 can also be made of other materials. This application does not limit the specific materials of the first housing 311 and the second housing 321.

[0052] In some embodiments, along a first direction, each of the core packages 20 has an electrode thinning area 40 at each end, the width of each electrode thinning area 40 is M, the first housing 311 includes two oppositely arranged first side plates 3111, the second housing 321 includes two oppositely arranged second side plates 3211, and the buffer distance between adjacent first side plates 3111 and second side plates 3211 is D1, the buffer distance D1 is the same as the width M of the electrode thinning area 40.

[0053] Specifically, during charging and discharging, the active materials of the positive and negative electrodes of the battery 100 undergo intercalation or deintercalation, resulting in material volume expansion. If the electrode thickness is uniform, stress concentration at the edges or electrode tab connections can easily lead to coating cracking or current collector breakage. Designing a thinning area 40 at the electrode edge can reduce local rigidity, evenly distribute mechanical stress, prevent crack propagation, and improve cycle life. However, when the core pack 20 expands, if the thinning areas 40 at both ends of the electrode fail to maintain good contact, it may lead to uneven current distribution, thereby affecting the performance of the battery 100. At the same time, areas of expansion and poor contact may also cause lithium ions to deposit or precipitate in these areas, forming lithium dendrites, which in severe cases may even lead to problems such as short circuits, capacity decay, or even fires in the battery 100.

[0054] Understandably, since the buffer distance D1 of the buffer section 32 is equal to the width M of the electrode thinning area 40, it can effectively adapt to volume expansion during the charging and discharging process of the battery 100, reduce contact problems caused by expansion, ensure that the electrode materials at both ends of the battery 100 always have good electrical contact, help slow down the deposition of lithium ions on the electrode surface, reduce lithium plating, and thus improve the safety and service life of the battery 100.

[0055] In some embodiments, the buffer distance D1 is between 10mm and 30mm. Specifically, the buffer distance D1 can be 10mm, 15mm, 20mm, 25mm, 30mm, etc., and is not limited herein.

[0056] Specifically, when the buffer distance D1 is less than 10mm, the buffer space is too small to accommodate cell expansion, which increases the safety risk of the battery. When the buffer distance is greater than 30mm, as charging and discharging increase, the portion of the buffer part 32 that extends beyond the electrode thinning area 40 will not fit tightly, resulting in unevenness and uneven stress on the electrode in the electrode thinning area 40. This can easily lead to lithium plating at the electrode edges, reducing the cycle life of the battery and also increasing the safety risk.

[0057] In some embodiments, see Figure 3 and Figure 5 Along the second direction, the first housing 311 includes two third side plates 3112 arranged opposite to each other along the second direction, and each end of the third side plate 3112 is connected to a first side plate 3111. The second housing 321 includes two fourth side plates 3212 arranged opposite to each other along the second direction, and each end of the fourth side plate 3212 is connected to a second side plate 3211.

[0058] The buffer distance between the adjacent third side plate 3112 and the fourth side plate 3212 is D2, which is between 10mm and 30mm, and the first direction and the second direction are different. Specifically, the buffer distance D2 can be 10mm, 15mm, 20mm, 25mm, 30mm, etc., and this application does not limit it.

[0059] In some embodiments, the buffer distance D2 and the buffer distance D1 are the same. Setting the same buffer distance facilitates the molding process of the buffer part 32 and enables the buffer part 32 to evenly distribute pressure, avoiding uneven force due to an excessively thin buffer distance, thereby extending the product's service life and improving its reliability.

[0060] In some embodiments, see Figure 3 and Figure 4Along a third direction, the thickness D3 of the buffer portion 32 is between 3μm and 5μm. Specifically, it can be 3μm, 3.2μm, 3.5μm, 4μm, 4.5μm, 4.7μm, 5μm, etc., and this application does not limit it.

[0061] Specifically, when the thickness of the buffer portion 32 is less than 3μm or greater than 5μm, the lithium ion transport distance between the central region and the edge region of the cell will be different due to the long-term repeated charging and discharging of the cell. This will easily lead to lithium plating in different regions of the electrode, reducing the battery's 100 cycle life and increasing safety risks.

[0062] In some embodiments, see Figure 3 and Figure 4 Along a third direction, the thickness D4 of the liquid storage section 31 is between 1 μm and 2 μm. Specifically, it can be 1 μm, 1.2 μm, 1.5 μm, 1.7 μm, 2 μm, etc., and this application does not limit it.

[0063] Specifically, when the thickness of the liquid storage section 31 is less than 1 μm, the electrolyte content in the liquid storage section 31 area is reduced, the amount of electrolyte replenishment for later cycles of the battery 100 is reduced, and there is no improvement effect on the safety performance of the battery 100; when the thickness of the liquid storage section 31 is greater than 2 μm, the middle of the core pack 20 expands, which will lead to poor contact around the battery 100 and lithium plating.

[0064] The first direction can be the length direction of the battery 100, the second direction can be the height direction of the battery 100, and the third direction can be the thickness direction of the battery 100. It is understood that the length, height, and thickness directions of the battery 100 may vary depending on the size of the battery 100, and this application does not limit the specific directions.

[0065] In some embodiments, the hardness of the first housing 311 is between Shore A 20HA and 40HA. Specifically, it can be 20HA, 25HA, 30HA, 35HA, 40HA, etc., which are not limited herein.

[0066] In some embodiments, the hardness of the second housing 321 is between Shore A 80HA and 100HA. Specifically, it can be 80HA, 85HA, 90HA, 95HA, 100HA, etc., which are not limited herein.

[0067] Understandably, if the hardness is too low, the first casing 311 and the second casing 321 are easily damaged due to the breathing effect of the battery 100's expansion force as the battery cell is repeatedly charged and discharged over a long period of time, resulting in a gradual decrease in capacity and performance. If the hardness is too high, the first casing 311 and the second casing 321 are easily punctured after being damaged, causing a short circuit inside the battery 100.

[0068] In some embodiments, see Figure 1 and Figure 2 The ratio of the length L1 of the buffer component 30 to the length L2 of the core package 20 is between 1.01 and 1.03. Specifically, the ratio can also be 1.01, 1.015, 1.02, 1.025, 1.03, etc., which are not limited in this application.

[0069] In some embodiments, see Figure 1 and Figure 2 The ratio of the height H1 of the buffer component 30 to the height H2 of the core package 20 is between 1.01 and 1.03. Specifically, the ratio can be 0.96, 0.965, 0.97, 0.975, 0.98, etc., which are not limited herein.

[0070] When the ratio of the length L1 of the buffer assembly 30 to the length L2 of the core package 20, or the ratio of the height H1 of the buffer assembly 30 to the height H2 of the core package 20, is less than 1.01, as the expansion of the middle part of the battery 100 increases, the internal space of the battery 100 decreases, and the lithium-ion transport distance of the thinned area 40 around the perimeter increases, which will lead to lithium deposition at the edge of the electrode, reduce the cycle life of the battery 100, and increase the safety risk.

[0071] When the ratio of the length L1 of the buffer component 30 to the length L2 of the core pack 20, or the ratio of the height H1 of the buffer component 30 to the height H2 of the core pack 20, is greater than 1.03, it will cause a decrease in the volumetric energy density of the cell, resulting in an increase in the manufacturing cost of the battery 100.

[0072] In some embodiments, the ratio of the length L1 of the buffer assembly 30 to the length L3 of the outer shell is between 0.96 and 0.98. Specifically, the ratio can be 0.96, 0.965, 0.97, 0.975, 0.98, etc., and is not limited herein.

[0073] Specifically, when the ratio of the length L1 of the buffer component 30 to the length L3 of the outer shell is less than 0.96, it will cause a decrease in the volumetric energy density of the battery cell and an increase in manufacturing costs; when the ratio of the length L1 of the buffer component 30 to the length L3 of the outer shell is greater than 0.98, it will lead to a reduction in the internal space of the battery cell, a reduction in the amount of electrolyte used, and a shortening of the battery's 100-cycle life.

[0074] In some embodiments, see Figure 1 and Figure 2 The ratio of the height H1 of the buffer component 30 to the height H3 of the outer shell is between 0.92 and 0.95. Specifically, the ratio can be 0.92, 0.925, 0.93, 0.935, 0.94, 0.945, 0.95, etc., which are not limited herein.

[0075] Specifically, when the ratio of the height H1 of the buffer assembly 30 to the height H3 of the outer casing is less than 0.92, it will cause a decrease in volumetric energy density and an increase in manufacturing cost. When the ratio of the height H1 of the buffer assembly 30 to the height H3 of the outer casing is greater than 0.95, it will lead to a reduction in the internal space of the cell, resulting in a reduction in the amount of electrolyte used and a shortening of the battery's 100-cycle life.

[0076] In some embodiments, the ratio of the volume of the buffer section 32 to the volume of the liquid storage section 31 is between 0.1 and 0.12.

[0077] Specifically, when the ratio of the volume of the buffer section 32 to the volume of the liquid storage section 31 is less than 0.1, the heat dissipation capacity of the buffer assembly 30 decreases, the temperature rise of the core pack 20 increases, and the cycle life decreases. When the ratio of the volume of the buffer section 32 to the volume of the liquid storage section 31 is greater than 0.12, the stress on the core pack 20 increases, the buffer section 32 breaks, and the electrolyte is released. The buffer space provided by the buffer assembly 30 decreases, and the effect of improving the expansion force of the battery 100 is reduced.

[0078] The battery 100 of this application can be a wound battery 100, which, due to its wound structure, has a high energy density and a small volume. The battery 100 of this application can also be a stacked battery 100, which is typically thinner and allows for flexible adjustment of size and shape. The battery 100 can also have other structural forms, which are not limited herein.

[0079] This application also provides a battery pack 100, which includes a housing with a receiving chamber. Multiple batteries 100 form a battery module, which is disposed within the receiving chamber. By using the battery 100 of this application, the safety and reliability of the battery pack are improved, making it suitable for various demanding battery 100 application scenarios, thereby enhancing the overall efficiency and performance of the battery 100.

[0080] This application also provides an electrical device, which includes a battery pack as described above, used to provide electrical energy to the device. The electrical device can be an electric vehicle, power tool, electric bicycle, energy storage system, drone, mobile device, etc. By incorporating a battery pack, the safety of the electrical device can be ensured, and its service life can be extended.

[0081] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery, characterized in that, include: shell; Multiple core packages are installed inside the housing and spaced apart. A buffer component, the buffer component comprising: A buffer section is sandwiched between two adjacent core packages; The liquid storage section is disposed within the buffer section. The liquid storage section includes a first housing and an electrolyte. The electrolyte is disposed within the first housing. The first housing can rupture and release the electrolyte when the core package expands to a preset state.

2. The battery according to claim 1, characterized in that, The buffer section includes a second housing and a buffer material, the buffer material being filled inside the second housing and covering the liquid storage section.

3. The battery according to claim 2, characterized in that, Along the first direction, the first housing includes two first side plates arranged opposite each other, the second housing includes two second side plates arranged opposite each other, the buffer distance between adjacent first side plates and second side plates is D1, each of the two ends of each core package is provided with an electrode thinning area, the width of each electrode thinning area is M, and the buffer distance D1 and the width of the electrode thinning area are equal.

4. The battery according to claim 3, characterized in that, The buffer distance D1 is between 10mm and 30mm.

5. The battery according to claim 3, characterized in that, Along the second direction, the first housing includes two third side plates arranged opposite each other along the second direction, and each end of the third side plate is connected to a first side plate. The second housing includes two fourth side plates arranged opposite each other along the second direction, and each end of the fourth side plate is connected to a second side plate. The buffer distance between adjacent third and fourth side plates is D2, which is between 10mm and 30mm. The first direction and the second direction are different.

6. The battery according to claim 5, characterized in that, Along a third direction, the thickness D3 of the buffer portion is between 3μm and 5μm, and / or; Along the third direction, the thickness D4 of the liquid storage section is between 1 μm and 2 μm; The third direction is different from the first and second directions.

7. The battery according to claim 2, characterized in that, The hardness of the first shell is between Shore A20HA and 40HA, and / or; The hardness of the second shell is between 80HA and 100HA on the Shore A scale.

8. The battery according to any one of claims 1-7, characterized in that, The ratio of the length L1 of the buffer assembly to the length L2 of the core package is between 1.01 and 1.03, and / or; The ratio of the height H1 of the buffer assembly to the height H2 of the core package is between 1.01 and 1.

03.

9. The battery according to any one of claims 1-7, characterized in that, The ratio of the length L1 of the buffer assembly to the length L3 of the outer shell is between 0.96 and 0.98, and / or; The ratio of the height H1 of the buffer assembly to the height H3 of the outer shell is between 0.92 and 0.

95.

10. The battery according to any one of claims 1-7, characterized in that, The ratio of the volume of the buffer section to the volume of the liquid storage section is between 0.1 and 0.

12.

11. A battery pack, characterized in that, Includes the battery as described in any one of claims 1-10.

12. An electrical appliance, characterized in that, Includes the battery pack as described in claim 11.

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