High-expansion-rate battery module

Abstract

The invention discloses a high-expansion-rate battery module which comprises a battery assembly formed by arranging a plurality of single batteries and elastic clamping plate assemblies located at the two ends of the battery assembly. The elastic clamping plate assembly comprises an inner clamping plate, a foam plate and an outer clamping plate which are sequentially arranged outwards from the battery assembly; the density of at least the two sides of the foam board is gradually increased from the inner surface to the outer surface. The areas with large density on the two sides of the outer surface support the outer clamping plate, and the outer clamping plate is not prone to breakage when bent.

Description

Technical Field

[0001] The present invention relates to the field of lithium batteries, and in particular to a high expansion rate battery module. Background Art

[0002] With the gradual maturity of metal lithium secondary battery technology, metal lithium secondary batteries can also achieve charging and discharging within a certain period, and the specific energy is as high as 530Wh / kg or more, which has great application value in the field of high specific energy. However, metal lithium secondary batteries lack the space for lithium ion embedding compared to traditional graphite negative electrode materials, so the charging process will have a significant volume expansion, especially the square soft-packaged metal lithium batteries, whose thickness expansion is generally up to 8% or more. When the metal lithium secondary battery expands, it will cause huge deformation of the module structure, generate huge extrusion force to the outside, and cause damage to the structure of the electrical equipment. The use of rubber pads for buffering will seriously increase the weight of the battery module, thereby losing the advantage of high specific energy. If the thickness of the metal lithium secondary battery is not squeezed, the negative metal lithium material inside the battery will be powdered in just a few weeks, and the negative active material will lose its activity and become dead lithium, which will not be able to participate in charging and discharging, and then cause rapid capacity decay. Metal lithium secondary batteries require a certain pressure for extrusion and will undergo large dimensional changes, which makes the lightweight design of metal lithium secondary battery modules difficult, and it is impossible to achieve a low structural proportion using existing methods. When the surface of the metal lithium secondary battery electrode is rigidly connected, the negative electrode metal lithium will be severely deformed, resulting in an increase in the internal current density and further an increase in the internal resistance.

[0003] CN117301645A "Consumable elastic splint and metal lithium battery module" provides an elastic splint, including an outer elastic splint, a middle foam consumable layer and an inner rigid splint. However, after multiple charge and discharge cycles, the elastic splint will still expand and contract due to multiple cycles, resulting in a break in the middle, which greatly reduces the battery cycle performance. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the outer clamping plate of a battery module with a high expansion characteristic battery is easy to break during the expansion and contraction process of the charge and discharge cycle, especially the metal lithium battery module.

[0005] In order to achieve the above-mentioned object, the present invention provides a high expansion rate battery module, comprising: a battery assembly composed of a plurality of battery cells with high expansion characteristics, and elastic clamping plate assemblies located at both ends of the battery assembly;

[0006] The elastic clamping plate assembly comprises an inner clamping plate, a foam plate and an outer clamping plate which are sequentially arranged outward from the battery assembly.

[0007] Optionally, the outer surface of the foam board includes a curved surface.

[0008] Optionally, the outer surface of the foam board includes a horizontal plane and two side curved surfaces; the horizontal plane is located at the center of the outer surface, and the two side curved surfaces are respectively tangent to the horizontal plane and are located on both sides of the horizontal plane.

[0009] Optionally, the density of the foam board gradually increases from the inner surface to the two side curved surfaces.

[0010] Optionally, the foam board is formed by pressing.

[0011] Optionally, the outer splint is formed by laminating multiple layers of elastic single plates.

[0012] Optionally, the elastic single plates are symmetrically pasted in sequence along the central axis to form an outer clamping plate, and the width of the pasting area of ​​the elastic single plates is smaller than the width of the elastic single plates.

[0013] Optionally, the inner clamping plate is a one-piece structure, and the inner clamping plate is made of a rigid material.

[0014] Optionally, a grid-like rigid frame is embedded inside the foam board.

[0015] Optionally, the battery cell is a metal lithium battery cell or a silicon-carbon battery cell.

[0016] The beneficial effects of the present invention are:

[0017] (1) The high expansion rate battery module provided by the present invention is provided with elastic clamping plate assemblies at both ends of the battery assembly, and the elastic clamping plate assembly includes an inner clamping plate, a foam plate and an outer clamping plate arranged in sequence from the battery assembly to the outside, wherein at least on both sides of the foam plate, the density gradually increases from the inner surface to the outer surface, and the areas with higher density on both sides of the outer surface provide support for the outer clamping plate, so that the outer clamping plate is not easy to break when it is bent.

[0018] (2) The elastic splint assembly of the present invention includes a foam board as an interlayer, which can meet the requirements of lightweight design.

[0019] (3) The foam board of the present invention can be compressed when the pressure is too high, which can protect the internal single battery from internal short circuit due to excessive pressure, and meets the requirements of safety design of high expansion rate battery modules.

[0020] (4) The grid-like rigid frame embedded inside the foam of the present invention can improve the stability of the foam structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of the high expansion rate battery module of the present invention.

[0022] Figure 2It is a schematic structural diagram of the elastic splint assembly of the present invention.

[0023] Figure 3 It is a side view of the foam board of the present invention.

[0024] Figure 4 It is a side view of the foam board of the present invention before being pressed and formed.

[0025] Figure 5 It is a top view of the outer splint of the present invention.

[0026] Figure 6 The present invention is a schematic structural diagram of a foam board inlaid with a grid-like rigid frame.

[0027] Figure 7 It is a structural schematic diagram of a grid-like rigid frame of the present invention.

[0028] In the figure, 1-inner plywood, 2-foam board, 201-inner surface, 202-horizontal plane, 203-side curved surface, 204-foam body, 205-grid-like rigid frame, 3-outer plywood, 31-central axis, 32-adhesive area, 4-battery assembly, 5-binding wire. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] like Figure 1-Figure 2 As shown, the present invention provides a high expansion rate battery module, including: a battery assembly 4 composed of a plurality of battery cells with high expansion characteristics, and elastic clamping plate assemblies located at both ends of the battery assembly. The battery cell is one of a metal lithium battery cell or a silicon carbon battery cell. The elastic clamping plate assembly includes an inner clamping plate 1, a foam plate 2 and an outer clamping plate 3 arranged outward from the battery assembly in sequence. The battery assembly 4 and the elastic clamping plate assembly are fixed by winding a binding wire 5.

[0033] During the charging process of the high expansion rate battery module, the battery assembly 4 will undergo significant volume expansion, squeezing the elastic clamp assembly. The elastic clamp assembly will bend after being squeezed, especially the outer clamp 3 is prone to break due to excessive bending. The bending of the elastic clamp assembly is specifically manifested in that the areas close to the two sides of the elastic clamp assembly (away from the central axis of the elastic clamp assembly) bend toward the direction close to the battery assembly 4, causing the strength of the areas away from the central axis of the elastic clamp assembly and located on both sides to increase. Therefore, in the foam board provided by the present invention, at least on both sides of the foam board 2, its density gradually increases from the inner surface to the outer surface, and the strength of the foam will increase with the increase of density. The change trend of the density is compatible with the change trend of the elastic strength of the outer clamp 3 caused by bending. The areas with higher density on both sides of the outer surface of the foam board provide support for the outer clamp 3, making the outer clamp 3 not easy to break.

[0034] The outer surface of the foam board includes a curved surface. In some embodiments, Figure 3 As shown, the outer surface of the foam board 2 includes a horizontal plane 202 and two side curved surfaces 203; the horizontal plane 202 is located at the center of the outer surface, and the two side curved surfaces 203 are respectively connected to the horizontal plane 202, and there is a smooth transition between the side curved surfaces 203 and the horizontal plane 202, and the side planes 203 are located on both sides of the horizontal plane 202. The density of the foam board 2 gradually increases from the inner surface 201 of the foam board to the direction of the two side curved surfaces 203. The minimum radius of the side curved surface 203 is R, and R is the bending radius at which the outer splint 3 will not be damaged. R is a parameter related to the thickness and toughness of the outer splint 3. The actual minimum bending radius of the outer splint 3 can be confirmed by experiment, and the minimum bending radius is used as the value of R. In other embodiments, the outer surface of the foam board is an arc surface as a whole.

[0035] In the present invention, the foam board 2 is formed by pressing. First, a Figure 4 The foam board shown in the figure has a thickness of H0 (thickness direction Figure 4 The outer surface of the foam board is compressed near the two sides so that the two sides of the outer surface are symmetrically formed as shown in the figure. Figure 3The two side curved surfaces 203 are shown. After compression, the distance between the inner surface 201 of the foam board 2 and the horizontal plane 202 is h0, where h0≤H0.

[0036] In some embodiments, the foam board 2 is a PMI (polymethacrylimide) foam board with a density of 0.1 g / cm 3 -0.3g / cm 3 . The outer plywood 3 is composed of multiple layers of elastic veneers stacked together. The elastic veneer can be made of materials such as carbon fiber plate or elastic metal plate. When the thickness of each layer of elastic veneer is too thick, bending can easily lead to breakage and the deformation amplitude is too small. When the thickness is too thin, although bending can overcome the above-mentioned shortcomings, too many layers are required and the weight is too heavy. Optionally, the thickness of each layer of elastic veneer is 0.5mm-1.5mm. The outer plywood 3 is composed of 2-6 layers of elastic veneers. The inner plywood 1 is a carbon fiber plate or a metal plate. The inner plywood 1 is a one-piece structure and is made of rigid material. The design of the inner plywood 1 needs to have rigidity, and a flexible design is not adopted. The inner plywood 1 is set as one piece to protect the battery from deformation to the greatest extent. The inner plywood 1, the foam board 2 and the outer plywood 3 are pasted in sequence.

[0037] like Figure 2 and Figure 5 As shown, multiple layers of elastic veneers are sequentially pasted in symmetrical areas along the central axis 31 to form an outer clamping plate 3. The size of each layer of elastic veneer is the same, and the pasting area 32 of each layer of elastic veneer is the same, and the pasting area 32 is symmetrical along the central axis of the veneer. The width of the elastic veneer is M, and the width of the pasting area is N, N<M. Therefore, there is an unpasted area on the surface of the elastic veneer, and the area outside the pasting area 32 is the area where the veneer is bent and deformed, providing a free deformation space for the veneer.

[0038] like Figure 6 As shown, the foam board 2 may also be inlaid with a grid-like rigid frame (see Figure 7 ), by integrating the foam body 204 and the rigid frame 205, the pressure bearing capacity of the foam board is improved, and the overall structural stability of the foam board 2 is improved.

[0039] In summary, the present invention provides a high expansion rate battery module, wherein elastic clamping plate assemblies are respectively provided at both ends of the battery assembly, and the elastic clamping plate assembly includes an inner clamping plate, a foam plate and an outer clamping plate which are arranged in sequence outward from the battery assembly, wherein, at least on both sides of the foam plate, the density gradually increases from the inner surface to the outer surface, and the outer clamping plate is supported by the areas with higher density on both sides of the outer surface. When the outer clamping plate is bent, it is not easy to break, and the compressive strength and structural stability of the foam plate are improved by inlaying a grid-like rigid frame inside the foam plate.

[0040] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A high expansion rate battery module, characterized in that: include: A battery assembly consisting of a plurality of battery cells arranged in an array, and elastic clamping plate assemblies located at both ends of the battery assembly; The elastic clamping plate assembly comprises an inner clamping plate, a foam plate and an outer clamping plate which are sequentially arranged outward from the battery assembly; The outer surface of the foam board comprises a horizontal plane and two side curved surfaces; the horizontal plane is located at the center of the outer surface, and the two side curved surfaces are respectively tangent to the horizontal plane and are located on both sides of the horizontal plane.

2. The high expansion rate battery module according to claim 1, characterized in that: A grid-shaped rigid frame is inlaid inside the foam board.

3. The high expansion rate battery module according to claim 1, characterized in that: The outer surface of the foam board comprises a curved surface.

4. The high expansion rate battery module according to claim 1, characterized in that: The density of the foam board gradually increases from the inner surface to the two side curved surfaces.

5. The high expansion rate battery module according to claim 1, characterized in that: The foam board is formed by pressing.

6. The high expansion rate battery module according to claim 1, characterized in that: The outer clamping plate is formed by stacking multiple layers of elastic single plates.

7. The high expansion rate battery module according to claim 6, characterized in that: The elastic single plates are symmetrically pasted in sequence along the central axis to form an outer clamping plate, and the width of the pasting area of ​​the elastic single plates is smaller than the width of the elastic single plates.

8. The high expansion rate battery module according to claim 1, characterized in that: The inner clamping plate is a one-piece structure and is made of a rigid material.

9. The high expansion rate battery module according to claim 1, characterized in that: The battery cell includes at least one of a metal lithium battery cell or a silicon carbon battery cell.

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