A breathable lithium-ion battery module structure

Abstract

This invention relates to a breathable lithium-ion battery module structure, including fasteners, front and rear wall panels, a silicon anode lithium-ion battery, a pull rod, and a breathing plate. The silicon anode lithium-ion battery is fixed by the pull rod, fasteners, and front and rear wall panels. The breathing plate is placed between the silicon anode lithium-ion battery and the front wall panel. The breathing plate is a composite material structure, combining metal and polymer materials to achieve a structure with low elastic modulus and high elastic deformation capability. The breathing plate integrates a thermistor for monitoring temperature information at characteristic locations of the battery pack.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology and relates to a lithium-ion battery module structure, particularly suitable for silicon anode lithium-ion battery module structures. Background Technology

[0002] Lithium-ion batteries, with their high energy density, are widely used in the new energy vehicle field. To further improve the energy density of lithium-ion batteries, silicon anode lithium-ion batteries offer a significant improvement over traditional graphite anode lithium-ion batteries, showing promising application prospects. However, due to the high expansion characteristics of silicon anode lithium-ion batteries—lithium intercalation in silicon can expand the volume by up to 300%—the battery volume exhibits significant expansion and contraction during cycling. Traditional lithium-ion battery modules typically use fixed-end constraints, keeping the battery in a compressed state. However, the high volume expansion of silicon anode lithium-ion batteries leads to increased internal stress levels within the battery module. This high stress increases internal polarization, affecting battery performance and further accelerating battery degradation. Simultaneously, the significant expansion and contraction of silicon anode lithium-ion batteries pose a significant challenge to battery module structural design. Summary of the Invention

[0003] The technical problem solved by this invention is to provide a breathable lithium-ion battery module structure that provides a good stress environment for the expansion and contraction of silicon anode batteries, thereby improving the overall performance and cycle life of the battery module.

[0004] The solution of this invention is: a breathable lithium-ion battery module structure, including fasteners, front and rear wall panels, a silicon anode lithium-ion battery, a pull rod, and a breathing plate; the silicon anode lithium-ion battery is fixed by the pull rod, fasteners, and front and rear wall panels; the breathing plate is placed between the silicon anode lithium-ion battery and the front wall panel; the breathing plate is a composite material structure, which combines metal materials and polymer materials to achieve a structure with low elastic modulus and high elastic deformation capability; the breathing plate integrates a thermistor to monitor the temperature information of characteristic positions of the battery pack.

[0005] Preferably, the low elastic modulus is an equivalent elastic modulus of 15 GPa to 20 GPa, and the maximum elastic deformation can reach 1 mm to 3 mm.

[0006] Preferably, the breathing plate includes a metal layer, a silicone layer, a corrugated plate, and a thermistor;

[0007] The corrugated plate is made of the same material as the metal layer. The two metal layers are connected to the corrugated plate by welding to form a breathing plate skeleton structure. Silicone is poured into the skeleton structure to fill the gaps in the skeleton structure. The silicone cures to form a silicone layer. A thermistor is integrated inside the metal layer.

[0008] Preferably, the radius of each arc of the corrugated plate is 8 mm to 10 mm, and the arc angle is 120° to 140°; the metal plate is welded to the apex of the arc of the corrugated plate; the thickness of the metal plate is 1 mm to 2 mm, and the length and width are 220 mm to 250 mm.

[0009] Preferably, the battery module has a double-row layout for individual cells, with 8 to 15 individual cells in each row; the individual cells are connected in series, parallel, or a combination of series and parallel.

[0010] Preferably, the silicon anode lithium-ion battery achieves sealing through a multi-point sampling battery cover structure; the battery cover is designed with two cylindrical flange structures, each flange structure having a cylindrical through hole inside, and symmetrical structures designed at both ends of the cylindrical through hole. The symmetrical structure includes trapezoidal grooves designed at both ends of the cylindrical through hole, a circular groove designed along the waistline of the trapezoidal groove, and a groove for installing guide plates designed at the outermost edge of the trapezoidal groove; the symmetrical structure is used to improve the battery cover structure's ability to withstand internal and external pressure differences; the guide plate is designed with multiple circular holes, and each enameled wire passes through one circular hole, and the battery cover flange structure is sealed by injecting structural adhesive into the inner cavity of the flange structure.

[0011] Preferably, a sealing and insulating component is placed between the battery cover and the terminal post, and bolts and nuts are used to fasten the terminal post and the battery cover to achieve the insulation and sealing functions.

[0012] Preferably, the angle between the bottom and the waist of the trapezoidal groove is 120°~150°. A circular groove is designed at half the height of the trapezoidal groove from the bottom edge. The height ratio of the cylindrical through hole to the trapezoidal groove is 2:1.

[0013] Preferably, a circular groove is provided on the inner wall of the cylindrical through hole, and the symmetrical structure is symmetrical with respect to the circular groove.

[0014] Preferably, the sealing and insulating component is made of polytetrafluoroethylene, and its structural design adopts an outwardly extending trapezoidal structure with an angle of 120°~150° between the upper base and the waist, so that the battery shell and the sealing and insulating component generate a wedge effect when the bolts are tightened.

[0015] The advantages of this invention compared to the prior art are:

[0016] The breathable lithium-ion battery module structure provided by this invention adds a highly elastic deformation structure inside the battery module by designing a breathing plate structure. This can absorb the deformation of the silicon anode lithium-ion battery during the cycle, ensuring that the battery is in a comfortable stress state and improving the cycle performance and life of the silicon anode lithium-ion battery.

[0017] This invention reduces the overall equivalent elastic modulus of the structure by welding the metal plate and the corrugated plate together. By injecting silicone into the battery structure, the corrugated plate and the silicone deform in coordination, achieving an equivalent elastic modulus of 15 GPa to 20 GPa for the breathing plate structure, and a maximum elastic deformation of 1 mm to 3 mm.

[0018] To further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings. However, the drawings are for reference and illustration only and are not intended to limit the present invention. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a breathable lithium-ion battery module structure according to the present invention;

[0020] Figure 2 Exploded view of the breathing plate;

[0021] Figure 3 To obtain exploded views of the battery cover structure from multiple points;

[0022] Figure 4 This is a cross-sectional view of the cylindrical flange structure of the battery cover;

[0023] Figure 5 This is a schematic diagram of the guide plate structure;

[0024] Figures 1 to 2 Number 1 is a fastener, number 2 is the front wall panel, number 3 is the breather plate, number 4 is the silicon negative electrode lithium-ion battery, number 5 is the pull rod, and number 6 is the rear wall panel. Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention, the following detailed description is provided in conjunction with preferred embodiments and accompanying drawings.

[0026] Figure 1 As shown, the present invention provides a breathable lithium-ion battery module structure, which includes a fastener 1, a front wall panel 2, a breathing plate 3, a silicon negative electrode lithium-ion battery 4, a pull rod 5, and a rear wall panel 6.

[0027] Figure 2 The label 31 represents the metal layer, label 32 represents the high-elasticity silicone, label 33 represents the high-elasticity corrugated board, and label 34 represents the thermistor.

[0028] The battery pack adopts a rod-type structure, with a front wall panel 2 and a rear wall panel 6. The silicon negative electrode lithium-ion battery 4 is fixed by a rod 5 and a fastener 1. The breathing plate 3 is placed between the front wall panel 2 and the silicon negative electrode lithium-ion battery 4, and a pre-tightening force is applied to the breathing plate 3 by the rod.

[0029] The breathing plate is a composite material structure that combines metal and polymer materials to achieve a structure with low elastic modulus and high elastic deformation capability. Furthermore, a thermistor is integrated inside the breathing plate to monitor temperature information at characteristic locations of the battery pack. This invention provides a breathable lithium-ion battery module structure for silicon anode batteries through the internal breathing plate design, ensuring that the silicon anode battery maintains a comfortable stress state during cycling and improving the cycle characteristics of silicon anode lithium-ion batteries. The breathing plate 3 has a three-layer structure, including a metal layer 31, high-elasticity silicone 32, a high-elasticity corrugated plate 33, and a thermistor 34. The metal layer 31 of the breathing plate 3 is made of aluminum alloy, and the corrugated plate 33 is made of the same material as the metal layer. The two metal layers and the corrugated plate are connected by welding to form the breathing plate skeleton structure. The thermistor 34 is attached to the inside of the metal layer, and then high-elasticity silicone (elastic modulus of approximately 1.2 GPa) is poured into the skeleton structure to fill the gaps. After the silicone cures, the breathing plate structure is formed. The breathing plate structure combines a metal structure with a polymer material to form a composite material. The metal material acts as a skeleton support, improving the overall structural stability and rigidity of the battery pack. Under normal pressure, the high-elasticity corrugated plate and high-elasticity silicone work together to absorb the expansion deformation of the silicon anode lithium-ion battery, generating significant elastic deformation. The composite structure of the breathing plate has high thermal conductivity, achieving its load-bearing function while also increasing the module's heat dissipation capacity. When the silicon anode lithium-ion battery undergoes delithiation and volume shrinkage, the breathing plate releases its deformation. Through the coordinated deformation of the breathing plate and the silicon anode lithium-ion battery, the battery remains within a comfortable stress range. The thermistor 34, designed inside the metal layer 31, is close to the main surface of the battery, allowing for better monitoring of battery temperature evolution and playing a crucial role in early warning of thermal runaway. The breathing plate structure consists of a metal plate, a high-elasticity corrugated plate, and silicone. The radius of each arc of the corrugated plate is 8mm~10mm, and the arc angle is 120°~140°. The metal plate is welded to the apex of the arc of the corrugated plate. The metal plate is 1mm to 2mm thick, with dimensions of 220mm to 250mm. Both the metal plate and the corrugated plate are made of 2A12 aluminum alloy with a high modulus of elasticity. The high-elasticity silicone injected inside the breather has an elastic modulus of approximately 1.2 GPa.

[0030] This invention can meet the requirements for battery pack assembly of silicon anode lithium-ion batteries under high expansion conditions, ensuring that the silicon anode lithium-ion batteries are in a comfortable stress state, and improving the cycle performance and lifespan of the battery module. The battery module's individual cells are arranged in a double-row layout, with 8 to 15 individual cells in each row; the individual cells are connected in series, parallel, or a combination of series and parallel connections.

[0031] Furthermore, the silicon anode lithium-ion battery of the present invention can be an existing product, or the battery cover structure can be improved by adopting the following technical solution to reliably bring out the internal sensor signal line of the battery under sealed conditions.

[0032] like Figure 3-5 As shown, the battery cover 13 and the terminal post 16 are first sealed by bolts and nuts 11. A sealing insulation component 14 is placed between the battery cover 13 and the terminal post 16. The sealing insulation component is made of polytetrafluoroethylene (PTFE), which has good plasticity and resistance to extreme environments. Its structural design adopts an outwardly expanding trapezoidal structure. When the bolts are tightened, the battery cover 13 and the sealing insulation component 14 generate a wedge effect, effectively enhancing the sealing performance of the battery casing. This achieves both insulation and sealing functions between the terminal post and the battery cover. A liquid injection hole is designed in the center of the battery cover. The battery terminal post and the battery cover are insulated by an insulation component 15, which is made of polyimide. The gasket 12 is preferably a disc-shaped piece made of stainless steel, which can effectively prevent the nut from loosening.

[0033] The battery cover 13 is made of aluminum alloy. To enable internal battery sensor information transmission, two sets of cylindrical flange structures are designed in the battery cover for the signal lines inside the battery to pass through. The flange structure is 20 mm high and 8 mm in outer diameter. The structure is small and has little impact on the battery cover space, so it will not significantly reduce the battery's energy density. At the same time, to ensure the battery's sealing, a groove structure is designed inside the flange structure. The groove structure helps to increase the contact area between the structural adhesive and the battery cover, improving the adhesion. Specifically, the main body of the flange structure's inner cavity is a cylindrical through hole. A symmetrical structure is designed at both ends of the cylindrical through hole. The symmetrical structure includes a trapezoidal groove at both ends of the cylindrical through hole, a circular groove designed along the waist line of the trapezoidal groove, and a groove for installing guide plates designed at the outermost edge of the trapezoidal groove. The symmetrical structure can ensure a large pressure difference between the inside and outside of the battery, thereby improving the battery cover structure's ability to withstand the stress of the internal and external pressure difference.

[0034] Circular guide plates 17, made of polyimide, are designed at the top and bottom of the battery cover flange structure. They are placed parallel to each other within the outermost groove of the flange structure, with the groove height matching the guide plate thickness. The guide plates have circular holes through which surface-insulated enameled wires pass. The guide plates ensure that the enameled wires are parallel, preventing contact between wires and ensuring the battery cover's seal. The flange structure is sealed by injecting high-strength structural adhesive. The inserted enameled wires can be used for the lead-out of signal lines from embedded sensors within the lithium-ion battery.

[0035] In use, first, thread the enameled wire 18 through the cylindrical hole. Then, insert guide plates onto the top and bottom sides of the enameled wire, with each wire threaded into a circular hole in the guide plate. Considering both signal transmission performance and battery cover assembly efficiency, 0.15 mm diameter enameled copper wire is preferred. Place the guide plate at the bottom of the battery cover close to the bottom of the flange, then pour structural adhesive into the top of the flange opening. Secure the guide plate at the top of the battery cover to the top of the flange opening, allowing the adhesive to fully cure for 3 hours. The guide plate has six circular holes. Two guide plates are placed on the top and bottom sides of the flange structure, with their circular holes corresponding vertically to ensure the enameled wires are parallel, preventing contact between them and ensuring the structural adhesive evenly coats each wire, thus guaranteeing the sealing of the battery cover flange structure. The wiring harness at the bottom of the battery cover can connect to the embedded sensor inside the battery, while the wiring harness at the top of the battery cover can connect to a signal acquisition device to transmit signals from inside the battery. Simultaneously, the flange structure guide plate features a multi-hole design, supporting multiple wire harness leads and providing distributed temperature sensor signal leads.

[0036] As described above, those skilled in the art can make other corresponding changes and modifications based on the technical solutions and concepts of this invention, and all such changes and modifications should fall within the protection scope of the appended claims of this invention.

Claims

1. A breathable lithium-ion battery module structure, characterized in that: The system includes fasteners, front and rear wall panels, a silicon anode lithium-ion battery, a pull rod, and a breather plate. The silicon anode lithium-ion battery is secured by the pull rod, fasteners, and front and rear wall panels. The breather plate is placed between the silicon anode lithium-ion battery and the front wall panel. The breather plate is a composite material structure, combining metal and polymer materials to achieve a structure with low elastic modulus and high elastic deformation capability. An integrated thermistor within the breather plate is used to monitor temperature information at key locations within the battery pack. The breathing plate includes a metal layer, a silicone layer, a corrugated plate, and a thermistor; The corrugated plate is made of the same material as the metal layer. The two metal layers are connected to the corrugated plate by welding to form a breathing plate skeleton structure. Silicone is injected into the skeleton structure to fill the gaps in the skeleton structure. The silicone cures to form a silicone layer. A thermistor is integrated inside the metal layer. The low elastic modulus is an equivalent elastic modulus of 15 GPa to 20 GPa, and the maximum elastic deformation is 1 mm to 3 mm.

2. The breathable lithium-ion battery module structure according to claim 1, characterized in that: The radius of each arc of the corrugated plate is 8 mm to 10 mm, and the arc angle is 120° to 140°; the metal plate is welded to the apex of the arc of the corrugated plate; the thickness of the metal plate is 1 mm to 2 mm, and the length and width are 220 mm to 250 mm.

3. The breathable lithium-ion battery module structure according to claim 1, characterized in that: The battery module's individual cells are arranged in a double-row layout, with 8 to 15 individual cells in each row; the individual cells are connected in series, parallel, or a combination of series and parallel.

4. The breathable lithium-ion battery module structure according to claim 1, characterized in that: The silicon anode lithium-ion battery achieves sealing through a multi-point sampling battery cover structure. The battery cover features two cylindrical flange structures, each with a cylindrical through-hole. Symmetrical structures are designed at both ends of the cylindrical through-hole, including trapezoidal grooves at both ends, a circular groove along the waistline of the trapezoidal groove, and a groove at the outermost edge of the trapezoidal groove for installing guide plates. These symmetrical structures enhance the battery cover's ability to withstand internal and external pressure differences. The guide plates have multiple circular holes, with each enameled wire passing through one hole. The battery cover flange structure is sealed by injecting structural adhesive into the inner cavity of the flange structure.

5. The breathable lithium-ion battery module structure according to claim 4, characterized in that: A sealing and insulating component is placed between the battery cover and the terminal post, and bolts and nuts are used to fasten it to achieve the insulation and sealing functions between the terminal post and the battery cover.

6. The breathable lithium-ion battery module structure according to claim 4, characterized in that: The angle between the bottom and waist of the trapezoidal groove is 120°~150°. A circular groove is designed at half the height of the trapezoidal groove from the bottom edge. The height ratio of the cylindrical through hole to the trapezoidal groove is 2:

1.

7. The breathable lithium-ion battery module structure according to claim 4, characterized in that: A circular groove is provided on the inner wall of the cylindrical through hole, and the symmetrical structure is symmetrical with respect to the circular groove.

8. The breathable lithium-ion battery module structure according to claim 4, characterized in that: The sealing and insulating component is made of polytetrafluoroethylene. Its structural design adopts an outwardly extending trapezoidal structure with an angle of 120°~150° between the top and the waist, which satisfies the wedge effect between the battery shell and the sealing and insulating component when the bolts are tightened.

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