Energy storage module structure for improving cycle life of lithium battery

Abstract

The utility model discloses an energy storage module structure for improving the cycle life of a lithium battery, which comprises a lithium battery module, the lithium battery module is composed of an elastic pressing end plate, a buffer end plate and a battery cell group clamped between the elastic pressing end plate and the buffer end plate, the battery cell group is composed of a plurality of lithium ion battery cells, and the lithium ion battery cells are arranged in the buffer end plate. A buffer pad is clamped and mounted between every two adjacent lithium ion battery cells, a wire harness isolation plate is mounted at the top of the battery cell group, two output holes and a plurality of battery cell connecting holes are formed in the wire harness isolation plate, connecting metal bars are mounted in the battery cell connecting holes, output pole metal bars are mounted in the output holes, and the output pole metal bars are connected with the output pole metal bars. The connecting metal bar is electrically connected to the lithium ion battery cell, the buffer end plate is provided with an output pole seat, and the battery cell group is electrically connected to the output pole seat through the output pole metal bar. According to the energy storage module structure, the cycle service life of the lithium battery can be prolonged, and the problems of function and safety failure are reduced.

Description

Technical Field

[0001] The utility model relates to the field of energy storage, in particular to an energy storage module structure for improving the cycle life of a lithium battery. Background Art

[0002] Current research has found that during use, lithium-ion batteries in energy storage products will continue to expand and deform due to the thickening of the SEI film and gas production, thereby generating an expansion force. As the battery life continues to decline, the expansion force will continue to increase. When the expansion force reaches a critical value, there are two risks that affect the cycle life and safety of the battery cell. First, the electrolyte infiltration of the positive and negative electrodes in the middle part of the large surface of the battery cell begins to deteriorate, eventually leading to lithium deposition and abnormal attenuation of the battery cell capacity. Second, the lithium battery structure deforms too much and even exceeds the tensile strength and cracks, posing a risk of damage to the battery's electrical connection or insulation protection.

[0003] Currently, the main method to reduce the expansion force of lithium batteries is to add buffer pads between the battery cells. The compression of the buffer pads can absorb part of the expansion force generated during the use of the lithium battery. However, this solution has several shortcomings:

[0004] It has limited absorption of the expansion force of lithium batteries and makes little contribution to the cycle life of lithium batteries;

[0005] It is difficult for the buffer pad to control the expansion force of the lithium battery within a constant range;

[0006] After long-term use and aging, the resilience and compressibility of the buffer pad deteriorate, which is not conducive to the release of the expansion force of the lithium battery. Utility Model Content

[0007] The purpose of the present invention is to provide an energy storage module structure that improves the cycle life of lithium batteries in order to solve the above problems.

[0008] The utility model achieves the above-mentioned purpose through the following technical solutions:

[0009] A storage module structure for improving the cycle life of a lithium battery includes a lithium battery module, wherein the lithium battery module consists of a spring-loaded end plate, a buffer end plate, and a cell group sandwiched between the spring-loaded end plate and the buffer end plate, the cell group consists of a plurality of lithium-ion cells, a buffer pad is sandwiched and installed between two adjacent lithium-ion cells, a wiring harness isolation plate is installed on the top of the cell group, two output holes and a plurality of cell connection holes are provided on the wiring harness isolation plate, a connecting metal bar is installed in the cell connection hole, an output pole metal bar is installed in the output hole, the connecting metal bar is electrically connected to the lithium-ion cell, an output pole seat is installed on the buffer end plate, and the cell group is electrically connected to the output pole seat via the output pole metal bar.

[0010] Furthermore, the buffer end plate is composed of two layers of flat shell plates, an upper layer and a lower layer, and a plurality of cavities arranged therebetween, and an arch bridge-shaped buffer sheet is arranged in the cavity.

[0011] Furthermore, the elastic end plate is a spring end plate or a spring plate end plate.

[0012] Furthermore, the spring end plate is composed of a first support plate, a second support plate and several springs, a spring embedded plate is embedded in one side of the second support plate, and the spring is arranged between the spring embedded plate and the first support plate; the spring end plate is composed of a first support plate, a second support plate and several springs, a spring embedded steel plate is embedded in one side of the second support plate, and the spring is hot-riveted between the first support plate and the spring embedded steel plate.

[0013] Furthermore, a first guide column and a second guide column are respectively provided facing each other on the spring embedded plate and the first support plate, and both ends of the spring are sleeved on the first guide column and the second guide column; a plurality of sleeve racks are installed on the first support plate, and a limiting clamping column matching the sleeve rack is installed on the second support plate, and the sleeve rack is sleeved on the limiting clamping column.

[0014] Furthermore, the connecting metal bar is composed of two welding plates and an intermediate tensile structure connecting the two welding plates, and the welding plates are welded to the poles of the lithium-ion battery cell.

[0015] Furthermore, the output pole metal bar is composed of an output arch bridge type connecting section, an output pole welding piece connected and installed on both sides of the output arch bridge type connecting section, and a fixed section.

[0016] Furthermore, it also includes a module placement box, in which the lithium battery module is placed.

[0017] Furthermore, the module placement box is provided with guide brackets at the inner corners of the box body, and a support bracket is provided on the inner wall of the module placement box. Furthermore, the intermediate tensile structure is an intermediate arch bridge type connecting section or a conductor.

[0018] The beneficial effect is that by releasing the expansion force of the lithium battery, the expansion force of the lithium battery is kept within a certain range, and the EOL expansion force is less than a certain critical value, the cycle life of the lithium battery can be improved;

[0019] By releasing the expansion force of lithium batteries, lithium batteries can be used normally during their life cycle, reducing functional and safety failure issues. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0021] Figure 2 This is a structural diagram of a lithium battery module of an energy storage module structure for improving the cycle life of a lithium battery as described in the present invention;

[0022] Figure 3 This is a structural diagram of a spring end plate of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0023] Figure 4 This is a structural diagram of a buffer end plate of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0024] Figure 5 This is a cross-sectional structural diagram of a buffer end plate of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0025] Figure 6 This is a diagram showing the structure of the metal bars connected to the energy storage module structure for improving the cycle life of a lithium battery according to an embodiment of the present invention;

[0026] Figure 7 This is a diagram of the output metal bar structure of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0027] Figure 8 This is a structural diagram of a lithium battery module of another energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0028] Figure 9 This is a structural diagram of a spring end plate of an energy storage module structure for improving the cycle life of a lithium battery according to the present invention;

[0029] Figure 10 This is a diagram of the limiting clamping column and sleeve frame arrangement structure of an energy storage module structure for improving the cycle life of a lithium battery according to the utility model;

[0030] Figure 11 This is a diagram of a structure of scattered metal bars in an embodiment of an energy storage module structure for improving the cycle life of a lithium battery as described in the present invention.

[0031] The following are the descriptions of the reference numerals:

[0032] 1. Lithium battery module; 2. Module placement box, 21. Support frame, 22. Guide bracket; 3. Spring-loaded end plate, 31. First support plate, 311. Second guide column, 32. Second support plate, 33. Spring embedded plate, 331. First guide column, 34. Spring, 35. Spring clip, 351. Arch structure, 352. Connecting piece, 3521. Positioning hole, 36. Limiting column, 37. Sleeve frame, 38. Spring clip inner Embedded steel plate, 381, positioning column; 4, buffer end plate, 41, flat shell plate, 42, arch bridge type buffer plate, 43, cavity; 5, buffer pad; 6, wire harness isolation plate; 7, connecting metal bar, 71, welding plate, 72, middle arch bridge type connecting section, 73, wire; 8, output pole metal bar, 81, output pole welding plate, 82, output arch bridge type connecting section, 83, fixed section; 9, output pole seat; 10, lithium-ion battery cell. DETAILED DESCRIPTION

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments: Example

[0034] like Figure 1-Figure 7 As shown, an energy storage module structure for improving the cycle life of a lithium battery includes a lithium battery module 1 and further includes a module placement box 2;

[0035] The lithium battery module 1 can be hoisted into the module placement box 2 by a hoisting tool. The lithium battery module 1 consists of a spring-pressed end plate 3, a buffer end plate 4, and a cell group sandwiched between the spring-pressed end plate 3 and the buffer end plate 4. The cell group consists of a plurality of lithium-ion cells 10. A buffer pad 5 is sandwiched and installed between two adjacent lithium-ion cells 10. The buffer pad 5 serves as a buffer structure between the two lithium-ion cells 10. The spring-pressed end plate 3 and the buffer end plate 4 serve as buffer limit structures on both end sides of the cell group, which can limit and buffer the lithium-ion cells 10 in the expansion direction.

[0036] A wiring harness isolation plate 6 is mounted on the top of the battery cell group. The wiring harness isolation plate 6 has two output holes and several battery cell connection holes. A connection metal bar 7 is mounted in the battery cell connection hole. An output pole metal bar 8 is mounted in the output hole. The connection metal bar 7 is electrically connected to the lithium-ion battery cell 10. An output pole seat 9 is mounted on the buffer end plate 4. The battery cell group is electrically connected to the output pole seat 9 via the output pole metal bar 8. The connection metal bar 7 can be an aluminum connection bar, a copper connection bar, an iron connection bar, or the like; and the output pole metal bar 8 can be an output pole aluminum bar, an output pole copper bar, an output pole iron bar, or the like.

[0037] In this embodiment, the buffer end plate 4 includes two upper and lower flat shell plates 41 and a plurality of cavities 43 provided therebetween. If there are multiple cavities 43, the cavities 43 are spaced apart from each other. An arch-bridge-shaped buffer sheet 42 is provided in at least one cavity. In one embodiment, the multiple cavities 43 are evenly distributed, and each cavity is provided with an arch-bridge-shaped buffer sheet 42. In another embodiment, the multiple cavities 43 are evenly distributed, and the arch-bridge-shaped buffer sheets 42 are distributed in an X shape, and so on. The left and right ends of the arch-bridge-shaped buffer sheet 42 are located on the inner side wall of the lower flat shell plate 41. There is a gap between the arched end of the arch-bridge-shaped buffer sheet 42 and the inner side wall of the upper flat shell plate 41. The buffer end plate 4 can be an integrally formed structure. The buffer end plate 4 can be made of aluminum alloy. The buffer end plate 4 and the spring-pressed end plate 3 jointly clamp the battery cell group to ensure the stability of the battery cell group structure. When the expansion force of the battery cell group continues to increase to a certain threshold, the buffer end plate 4 is deformed. Specifically, the flat shell plate 41 is deformed under force, and the cavity 43 is squeezed and deformed, absorbing the corresponding expansion deformation of the lithium-ion battery cell and releasing part of the expansion force of the module; the arch bridge type buffer sheet 42 can improve the strength and rigidity of the buffer end plate 4 to ensure that it can withstand the continuously increasing module expansion force during its service life without excessive deformation or cracking.

[0038] In this embodiment, the spring-pressing end plate 3 is a spring end plate, which is composed of a first support plate 31, a second support plate 32 and a plurality of springs 34. A spring inner plate 33 is embedded in one side of the second support plate 32, and the spring 34 is arranged between the spring inner plate 33 and the first support plate 31. The first support plate 31 and the second support plate 32 can be steel support plates, plastic support plates, or support plates of other materials; the spring inner plate 33 can be a metal plate or a plate of other high-strength materials.

[0039] A first guide post 331 is provided on the side of the spring inner plate 33 facing the first support plate 31, and a second guide post 311 is provided on the side of the first support plate 31 facing the spring inner plate 33. The first guide post 331 and the second guide post 311 are arranged opposite to each other, and the sum of the heights of the first guide post 331 and the second guide post 311 is less than the compressed height of the spring 34; the two ends of the spring 34 are respectively sleeved on the first guide post 331 and the second guide post 311; the spring 34 can be fixed to the first support plate 31 and the spring inner plate 33 by adhesive or other means.

[0040] The second support plate 32 can be injection molded from a common plastic material (such as PC, PC+ABS, etc.). A spring embedded plate 33 is provided on the contact surface with the spring. The front side is flat and contacts the large surface of the lithium-ion battery cell 10 to transmit the module expansion force and provide insulation protection between the battery cell and the spring. The spring 34 is made of spring steel, and the first support plate 31 is made of stainless steel. The spring end plate and the buffer end plate 4 clamp the battery cell group to ensure the stability of the battery cell group structure.

[0041] In this embodiment, the connecting metal bar 7 consists of two welding tabs 71 and an intermediate arch-bridge-shaped connecting section 72 connecting the two welding tabs 71. The welding tabs 71 and the intermediate arch-bridge-shaped connecting section 72 are integrally formed and can be formed by welding multiple layers of metal foil together through polymer diffusion welding. When the connecting metal bar 7 is an aluminum bar, the metal foil is aluminum foil; when the connecting metal bar 7 is a copper bar, the metal foil is copper foil; when the connecting metal bar 7 is an iron bar, the metal foil is iron foil, and so on. The two welding tabs 71 are respectively connected to the poles of two adjacent lithium-ion battery cells 10 (for example, by welding), thereby connecting the adjacent lithium-ion battery cells 10 in series.

[0042] In this embodiment, the output electrode metal bar 8 consists of an output arch bridge-shaped connecting section 82, output electrode welding tabs 81 connected and mounted on both sides of the output arch bridge-shaped connecting section 82, and a fixing section 83. It can be formed by integrating multiple layers of metal foil through polymer diffusion welding. When the output electrode metal bar 8 is an output electrode aluminum bar, the metal foil is aluminum foil; when the output electrode metal bar 7 is an output electrode copper bar, the metal foil is copper foil; when the output electrode metal bar 7 is an output electrode iron bar, the metal foil is iron foil, and so on. In one embodiment, there are two output electrode metal bars 8, with the two output electrode welding tabs 81 connected to the positive and negative electrodes of the battery cell group, respectively, and the two fixing sections 83 connected to the two output electrode seats, respectively. Specifically, the fixing sections 83 are provided with openings. When in use, the fixing sections 83 are placed on the corresponding output electrode seats 9, with the openings on the fixing sections 83 corresponding to the openings on the corresponding output electrode seats 9, and are fixed by screwing.

[0043] The output arch bridge connecting section 82 on the output pole metal bar 8 and the middle arch bridge connecting section 72 on the connecting metal bar 7 can be stretched and deformed to prevent the welding point between the aluminum bar and the lithium ion battery cell 10 from being damaged due to displacement when the lithium ion battery cell 10 is deformed.

[0044] In this embodiment, a guide bracket 22 is installed at the inner corner of the module placement box 2, which is used to limit the drop when the lithium battery module 1 is hoisted and placed. A support frame 21 is installed on the inner wall of the module placement box 2. The support frame 21 is a sheet metal part, and the guide bracket 22 is an aluminum extruded part, both of which are fixed to the sheet metal frame of the box by screws and nuts. Example

[0045] An energy storage module structure for improving the cycle life of a lithium battery is different from that of Example 1 in that Figures 8-11As shown, first, the spring-pressed end plate 3 of Example 2 is a spring-loaded end plate, which is composed of a first support plate 31, a second support plate 32 and a plurality of spring plates 35. A spring-loaded embedded steel plate 38 is embedded on one side of the second support plate 32. The spring plate 35 is hot-riveted between the first support plate 31 and the spring-loaded embedded steel plate 38. In one embodiment, the spring plate 35 is composed of two arch structures 351 and a connecting piece 352 in the middle. The connecting piece 352 is provided with a positioning hole 3521, and the spring-loaded embedded steel plate 38 is provided with a hole corresponding to the positioning hole 3521. The corresponding positioning column 381 passes through the positioning hole 3521 before hot riveting to position and fix the spring piece 35; in other embodiments, the positioning hole 3521 and the positioning column 381 can be omitted; in addition, the spring piece 35 can be one or three arch structures, or other numbers of arch structures. When the spring piece 35 is one arch structure, the connecting piece can be omitted or a connecting piece can be provided on one side or both sides of the arch structure; when the spring piece 35 includes 3 or more arch structures, connecting pieces can be provided between each arch structure.

[0046] A plurality of sleeve racks 37 are mounted on the first support plate 31. In this embodiment, the sleeve racks 37 are provided with four groups (or two, three, five, six, etc.), which are distributed at the edge of the side plate surface of the first support plate 31 (if the sleeve racks 37 are in an even group, they are generally symmetrically distributed on both sides of the side plate surface edge of the first support plate 31; if they are in an odd group, generally one side of the side plate surface edge of the first support plate 31 has one more group than the other side). A limiting post 36 matching the sleeve rack 37 is mounted on the second support plate 32. The sleeve rack 37 is sleeved on the limiting post 36, slides on it with a certain displacement, and is limited by the end limiting stop portion of the limiting post 36.

[0047] Secondly, the connecting metal bar 7 of Example 2 is composed of two welding pieces 71 and a wire 73 connecting the two welding pieces 71. The wire 73 can be fixed on the welding pieces 71 by ultrasonic welding and can be stretched and deformed.

[0048] It can be understood that the connecting metal bar 7 in Example 1 can also be composed of two welding plates 71 and a wire 73 connecting the two welding plates 71. The wire 73 can be fixed to the welding plates 71 by ultrasonic welding and can be stretched and deformed.

[0049] In the above embodiment, the connecting metal bar 7 assists in releasing the expansion force of the lithium-ion battery cell through the middle arch bridge-type connecting section or the wire, and the two sides are clamped by the spring-pressing end plate 3 and the buffer end plate 4. The expansion force of the lithium-ion battery cell 10 is released through the buffer pad, the spring-pressing end plate, and the buffer end plate. The spring-pressing end plate absorbs the displacement caused by the expansion and deformation of the module, and controls the expansion force of the module constantly within a certain range, so that the EOL expansion force of the lithium battery is less than a certain critical value, thereby improving the cycle life of the lithium battery.

[0050] Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments. The above-mentioned embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements shall fall within the scope of the present invention to be protected.

Claims

1. An energy storage module structure for improving the cycle life of a lithium battery, characterized by: It includes a lithium battery module, which consists of a spring-pressed end plate, a buffer end plate, and a battery cell group sandwiched between the spring-pressed end plate and the buffer end plate. The battery cell group consists of several lithium-ion battery cells, and a buffer pad is installed between two adjacent lithium-ion battery cells. A wire harness isolation plate is installed on the top of the battery cell group, and two output holes and several battery cell connection holes are provided on the wire harness isolation plate. A connecting metal bar is installed in the battery cell connection hole, and an output pole metal bar is installed in the output hole. The connecting metal bar is electrically connected to the lithium-ion battery cell, and an output pole seat is installed on the buffer end plate. The battery cell group is electrically connected to the output pole seat through the output pole metal bar.

2. The energy storage module structure for improving the cycle life of a lithium battery according to claim 1, characterized in that: The buffer end plate is composed of two layers of upper and lower flat shell plates and a plurality of cavities arranged therebetween, and an arch bridge type buffer sheet is arranged in the cavity.

3. The energy storage module structure for improving the cycle life of a lithium battery according to claim 1, characterized in that: The elastic pressure end plate is a spring end plate or a spring plate end plate.

4. The energy storage module structure for improving the cycle life of a lithium battery according to claim 3, characterized in that: The spring end plate is composed of a first support plate, a second support plate and several springs, a spring embedded plate is embedded in one side of the second support plate, and the spring is arranged between the spring embedded plate and the first support plate; the spring end plate is composed of a first support plate, a second support plate and several springs, a spring embedded steel plate is embedded in one side of the second support plate, and the spring is hot-riveted between the first support plate and the spring embedded steel plate.

5. The energy storage module structure for improving the cycle life of a lithium battery according to claim 4, characterized in that: The first guide column and the second guide column are respectively provided facing each other on the spring embedded plate and the first support plate, and the two ends of the spring are sleeved on the first guide column and the second guide column; a plurality of sleeve frames are installed on the first support plate, and a limiting clamping column matching the sleeve frame is installed on the second support plate, and the sleeve frame is sleeved on the limiting clamping column.

6. The energy storage module structure for improving the cycle life of a lithium battery according to claim 1, characterized in that: The connecting metal bar consists of two welding pieces and an intermediate tensile structure connecting the two welding pieces, and the welding pieces are welded to the poles of the lithium-ion battery cell.

7. The energy storage module structure for improving the cycle life of a lithium battery according to claim 1, characterized in that: The output pole metal bar is composed of an output arch bridge type connecting section, an output pole welding piece connected and installed on both sides of the output arch bridge type connecting section, and a fixed section.

8. The energy storage module structure for improving the cycle life of a lithium battery according to claim 1, characterized in that: It also includes a module placement box, in which the lithium battery module is placed.

9. The energy storage module structure for improving the cycle life of a lithium battery according to claim 8, characterized in that: The module placement box is provided with guide brackets at the inner corners of the box body, and the inner wall of the module placement box is provided with support brackets.

10. The energy storage module structure for improving the cycle life of a lithium battery according to claim 6, characterized in that: The intermediate tensile structure is an intermediate arch bridge type connecting section or a conducting wire.

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