Flat square shell lithium ion battery module

Abstract

The utility model discloses a flat square shell lithium ion battery module, which comprises an outer shell and a plurality of battery cells arranged in the outer shell and arranged in a flat mode, the outer shell comprises two trays, a metal plate right panel and a metal plate left panel, the metal plate right panel and the metal plate left panel are respectively connected with two ends of the trays, and all the battery cells are arranged in multiple layers. The two trays are distributed above and below the battery cell, and the battery cell pole and the anti-explosion valve on the battery cell are in a horizontal state and are positioned between the two trays. According to the flat-lying square-shell lithium ion battery module disclosed by the utility model, the size requirement in the height direction is greatly reduced by arranging the battery cells in a flat-lying manner, meanwhile, the positive electrode, the negative electrode and the anti-explosion valve are positioned in the horizontal direction, the insulation and short-circuit risks caused by relatively close distance to a metal plate tray are avoided, and the anti-explosion valve is horizontally arranged, so that the safety of the battery is improved after the battery cells are out of control. The sprayed electrolyte has a heat spreading effect on other cells, thermal runaway spreading caused by runaway of the cells is prevented, and the reliability is improved.

Description

Technical Field

[0001] This utility model belongs to the field of lithium-ion battery energy storage application technology. Specifically, this utility model relates to a flat-lying square-shell lithium-ion battery module. Background Technology

[0002] Currently, most new energy vehicle power batteries use lithium-ion batteries. Lithium-ion batteries have better safety performance and cost. More and more new energy vehicle manufacturers and energy storage stations are using lithium iron phosphate batteries. Lithium iron phosphate batteries are larger in size than ternary lithium-ion batteries, have lower volumetric energy density, and require more extreme cell structure layout, especially in terms of height space requirements.

[0003] Due to the structural characteristics of lithium iron phosphate lithium-ion batteries, the height of a single cell is generally relatively high, and the nominal voltage of the battery is usually 3.2V. To achieve the voltage platform and capacity requirements of the battery system, the cells are usually designed in series and parallel. Prismatic lithium-ion battery packs primarily employ a vertically stacked cell configuration, resulting in close contact between the large surfaces of the cells. This leads to slow heat dissipation from the internal cells and a significant overall temperature difference within the battery module. Prolonged use with such high temperature variations can shorten cell lifespan, impacting product safety and customer experience. Furthermore, the vertical cell arrangement requires substantial vertical space in the battery system. With the positive and negative terminals and explosion-proof valves facing upwards and close to the battery's upper casing (a sheet metal structure), the positive and negative terminals and explosion-proof valves are susceptible to short circuits or thermal runaway when subjected to pressure or impact. Additionally, the proximity of the positive and negative terminals and explosion-proof valves to the top cover (also a sheet metal structure) means that if the explosion-proof valve bursts, electrolyte spraying onto the sheet metal cover can cause short circuits and arcing, exacerbating thermal runaway and potentially leading to thermal runaway in other cells. This can result in a power interruption of the battery system and, in severe cases, a fire risk, posing a significant threat to vehicle occupants and the surrounding environment.

[0004] Currently, battery module designs employ an end plate and side plate structure with upright cells. Cells are isolated by buffer pads, and only the narrow side of the cell is bonded to the side plate with structural adhesive. This results in insufficient constraint in the Z-direction of the cells. After the battery system is assembled, the overall strength and rigidity of the battery module itself and the battery system's installation on the vehicle body are inadequate. Consequently, under vibration, mechanical shock, and extreme operating conditions, cell migration is prone to occur, leading to busbar welding and voltage acquisition failure, resulting in power interruption. In severe cases, contact with the top cover or short circuit due to cell migration can cause thermal runaway and fire. Furthermore, many upright battery modules are currently limited by height and space constraints, and data acquisition methods often use FPC (Flexible Printed Circuit) methods. The cell-end acquisition uses nickel-plated connections. Because the cell welding process has stringent requirements, defects such as over-soldering and incomplete soldering are extremely difficult to control, and rework is extremely difficult once they occur.

[0005] Chinese Patent Application No. 201410181694.3 discloses a layered soft-pack lithium-ion battery module and its battery pack. This layered soft-pack lithium-ion battery module comprises multiple basic units, each including a soft-pack lithium-ion power battery, an outer frame, a heat sink, and elastic damping pads. A battery pack, constructed by stacking multiple of these layered soft-pack lithium-ion battery modules based on desired capacity, is connected via conductive sheets to achieve parallel or series connection between the battery modules. A single-layer module is expanded from multiple basic units, and the number of basic units in each single-layer module can be adjusted according to various objective conditions. The battery pack can be flexibly expanded according to the space provided by the vehicle, facilitating its layout.

[0006] The aim is to provide an improved flat-lying cubic lithium-ion battery module, particularly a shielding element that improves the appearance of the corner area. Utility Model Content

[0007] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention provides a flat-lying prismatic lithium-ion battery module, the purpose of which is to prevent the spread of thermal runaway caused by cell failure and improve reliability.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a flat-lying square-shell lithium-ion battery module, including an outer shell and multiple battery cells arranged in a flat manner inside the outer shell. The outer shell includes two trays and a sheet metal right panel and a sheet metal left panel connected to the two ends of the trays respectively. All battery cells are arranged in multiple layers. The two trays are distributed above and below the battery cells. The battery cell terminals and explosion-proof valves on the battery cells are in a horizontal state and located between the two trays.

[0009] Intercellular aerogel is disposed between the battery cells.

[0010] A first epoxy board is disposed between the tray and the battery cell, and a second epoxy board is disposed between the battery cell and the right and left panels of the sheet metal.

[0011] The battery cell has a first insulating film and a second insulating film distributed on both sides.

[0012] The first insulating film and the second insulating film are PC insulating films.

[0013] A busbar support is provided between the first insulating film and the battery cell, and a first aluminum busbar, a second aluminum busbar and a third aluminum busbar are provided on the busbar support.

[0014] The first aluminum busbar, the second aluminum busbar, and the third aluminum busbar are snapped onto the busbar bracket.

[0015] This utility model's flat-lying square-shell lithium-ion battery module significantly reduces the height dimension requirements by arranging the cells in a flat manner. At the same time, the positive and negative electrodes and the explosion-proof valve are in a horizontal position, avoiding the risk of insulation and short circuits caused by close proximity to the sheet metal tray. The horizontal arrangement of the explosion-proof valve mitigates the thermal spread of the sprayed electrolyte to other cells after a cell runs away, preventing the spread of thermal runaway caused by cell runaway and improving reliability. Attached Figure Description

[0016] This manual includes the following figures, which illustrate the following:

[0017] Figure 1 This is a schematic diagram of the overall external structure of a flat-lying square-shell lithium-ion battery module device according to this utility model;

[0018] Figure 2 This is a schematic diagram of the overall exploded structure of a flat-lying square-shell lithium-ion battery module device according to this utility model;

[0019] Figure 3 This is a schematic diagram of the sheet metal structure of a flat-lying square-shell lithium-ion battery module device according to this utility model.

[0020] Figure 4 This is a schematic diagram of the insulation and protection structure of a flat-lying square-shell lithium-ion battery module device according to this utility model; Figure 5 This is a schematic diagram of a flat-lying square-shell lithium-ion battery module busbar support structure according to this utility model;

[0021] Figure 6 This is a schematic diagram of the connection row structure of a flat-lying square-shell lithium-ion battery module device according to this utility model;

[0022] Figure 7 This is a schematic diagram of the data acquisition harness structure of a flat-lying square-shell lithium-ion battery module device according to this utility model. Detailed Implementation

[0023] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of this utility model, and to facilitate its implementation.

[0024] like Figures 1 to 7As shown, this utility model provides a flat-lying square-shell lithium-ion battery module, including an outer shell and multiple battery cells 9 arranged in a flat manner inside the outer shell. The outer shell includes two trays 1 and a sheet metal right panel 2 and a sheet metal left panel 3 fixedly connected to the two ends of the trays 1 respectively. All battery cells 9 are arranged in two layers, with the two trays 1 distributed above and below the two layers of battery cells 9. The battery cell terminals and explosion-proof valves on the battery cells 9 are in a horizontal state and located between the two trays 1. The battery cell terminals and explosion-proof valves are parallel to the trays 1, and the trays 1 are in a horizontal state. The sheet metal right panel 2 and the sheet metal left panel 3 are in a vertical state. The battery cell terminals include battery cell positive terminals and battery cell negative terminals.

[0025] Specifically, in this invention, the battery cells are arranged in a flat configuration, with the positive and negative terminals and the explosion-proof valve horizontally positioned. The positive and negative terminals and the explosion-proof valve are positioned away from the sheet metal tray, and are stacked and contacted via narrow surfaces. The larger surfaces are isolated from the battery cells, and thermal protection is achieved by adding aerogel to prevent the spread of thermal runaway caused by battery cell failure. Two trays 1, along with the right and left sheet metal panels 2 and 3, form a U-shaped outer shell. The outer shell encloses two layers of battery cells. Epoxy boards are directly added between the sheet metal parts and the battery cells for insulation. Airtight adhesive is used for insulation and high-temperature isolation between the large contact surfaces of the battery cells. Two-component polyurethane structural adhesive is used to bond the battery cells to the epoxy board, the airtight adhesive, and the sheet metal parts. An insulating film is applied to the bottom of the module for protection. The aluminum busbar, plastic bracket, and wire harness are pre-fixed to form a CCS (Cells Contact System) assembly. The CCS assembly is assembled with the module sheet metal parts by fasteners. The aluminum busbar and the battery cells are connected in series and parallel by welding. The module acquisition wire harness is connected to the battery cell connection busbar by fasteners. The rear end of the wire harness can be disassembled. The first and second insulating films are made of PC (insulating flame retardant polycarbonate) insulating film and are connected by plastic rivets.

[0026] like Figure 1 , Figure 2The diagram shows the overall external structure and exploded view of a flat-lying cubic lithium-ion battery module. The module mainly includes a first epoxy plate 4 and a second epoxy plate 5 for protecting and encasing the battery cell 9; a 1P8S module acquisition harness assembly 10 for voltage and temperature acquisition of the lithium-ion module assembly 25; M5 hexagonal flange nuts 17 mounted on the tray 1, the right sheet metal panel 2, and the left sheet metal panel 3; a second insulating film 8 and inter-cell aerogel 6 for protecting the bottom of the battery cell 9 and the area between the battery cells; and a busbar bracket 14 for connecting the tray 1 and the busbar support. The system includes: M4*8 Phillips head countersunk screws 16; first aluminum busbars 11, second aluminum busbars 12, and third aluminum busbars 13 for snapping onto the busbar bracket 14; M4 hexagonal flange nuts 15 for connecting the first aluminum busbars 11, second aluminum busbars 12, third aluminum busbars 13, battery cell 9, and 1P8S module acquisition harness assembly 10; module lifting holes 20 for transporting and hoisting the lithium-ion module assembly 25; M4x10 plastic screws 23 for fixing the first insulating film 7 to the busbar bracket 14; and module tags 24 for tracing the production process of the lithium-ion module assembly 25.

[0027] like Figure 3 , Figure 4 The diagram shows a schematic of the sheet metal structure and insulation protection structure of a flat-lying square-shell lithium-ion battery module. The module includes M5x12 snap-fit ​​screws 19 for connecting the tray 1, the right sheet metal panel 2, and the left sheet metal panel 3; sheet metal screw countersunk holes 22 for fixing the busbar bracket 14 and the tray 1 with M4*8 Phillips head countersunk screws 16; M6 projection weld nuts 18 for extending the connection of the lithium-ion module assembly 25; module lifting holes 20 for lifting the lithium-ion module assembly 25; and a first epoxy board 4, a second epoxy board 5, and inter-cell aerogel 6 for filling and isolating the battery cells 9, protecting the space between the tray 1, the right sheet metal panel 2, and the left sheet metal panel 3. Inter-cell aerogel 6 is provided between the two layers of arranged battery cells. A first epoxy board 4 is set between the tray 1 and the two layers of battery cells 9. The first epoxy board 4 is set horizontally. A second epoxy board 5 is set between the right sheet metal panel 2 and the two layers of battery cells 9. A second epoxy board 5 is set between the left sheet metal panel 3 and the two layers of battery cells 9.

[0028] like Figure 5 , Figure 6 , Figure 7The diagram shows a schematic of a flat-lying square-shell lithium-ion battery module busbar support structure, a connecting busbar structure, and a data acquisition harness structure. Its main structures include: an output electrode fixing insert 26 for fixing the first aluminum busbar 11; M4 rivet holes 28 for fixing the first insulating film 7, the busbar support 14, and M4x10 plastic screws 23; a busbar support cable groove 29 for constraining the 1P8S module data acquisition harness assembly 10; a busbar slot 30 for fixing the first aluminum busbar 11, the second aluminum busbar 12, and the third aluminum busbar 13 to the busbar support 14; and a connection for the busbar support. 14. The busbar bracket fixing knurled insert 27 of tray 1 and M4*8 Phillips head countersunk screw 16; including aluminum busbar fixing holes 31 for fixing the first aluminum busbar 11 and output pole fixing insert 26; including M4x10 press-fit screws 32 on the connecting busbar for fixing the 1P8S module acquisition harness assembly 10, the first aluminum busbar 11, the second aluminum busbar 12, the third aluminum busbar 13, and the M4 hexagonal flange nut 15; including aluminum busbar welding surface 33 for ensuring welding quality; including voltage acquisition OT terminal 34 and temperature acquisition OT terminal 35 for acquisition connection of 1P8S module acquisition harness assembly 10.

[0029] The high-current prismatic lithium-ion battery module with the above-described structure has the following advantages:

[0030] This utility model presents a horizontally oriented, square-shell lithium-ion battery module designed to meet the development needs of PACK systems with limited height space. The horizontal cell arrangement significantly reduces the dimensional requirements in the height direction. Simultaneously, the positive and negative electrodes and the explosion-proof valve are positioned horizontally, avoiding insulation and short-circuit risks caused by close proximity to the sheet metal cover. The horizontal arrangement of the explosion-proof valve, facing both sides of the PACK housing, mitigates the thermal spread of electrolyte sprayed from one cell to other cells in the event of a runaway cell. Furthermore, the addition of epoxy boards and aerogel insulation between the large surfaces of the cells, along with a two-component structural adhesive bonding process, results in higher overall strength and rigidity of the cells, lower temperature rise and temperature difference, and reduced thermal runaway propagation. The sheet metal U-shaped structure effectively solves the problem of insufficient constraint of the cells in the Z-direction. Standard parts are used for connection at the module's data acquisition points, facilitating rework and repair due to defects in the module wiring harness and processes. At the same time, the appropriate bolt torque avoids over-soldering and incomplete soldering defects caused by welding methods. The busbar, plastic bracket, and wiring harness are highly integrated with CCS components and secured to the sheet metal bracket using standard parts. This effectively ensures the correct positioning of the busbar relative to the cell welding points, the wiring harness acquisition points, and achieves higher assembly efficiency. The module can be connected in series via sheet metal side plates to increase the voltage platform, meeting standard 24V and 48V requirements. A heating film can be integrated at the bottom of the module for heating. The entire module is encased in sheet metal, reducing the risk of impacts and compression during production and shipping. The battery cells are well protected, and disassembly and assembly are convenient, preventing the risk of short circuits due to accidental contact with foreign objects during module production and PACK assembly.

[0031] like Figures 1 to 7 As shown, the assembly process of the above-described flat-sided prismatic lithium-ion battery module includes the following steps:

[0032] S1: Place a single tray 1 horizontally on the workbench and use M4*8 Phillips head countersunk screws 16 to fix the tray 1 to the busbar bracket 14.

[0033] S2: Apply two-component structural adhesive to the inner surface of a single tray 1.

[0034] S3: After the adhesive is applied, the first epoxy board 4 is pasted onto the adhesive tray 1, and the two-component structural adhesive is applied to the other side of the first epoxy board 4.

[0035] S4: Place the battery cell 9 flat on the first epoxy board 4 with adhesive according to the required positive and negative electrode arrangement (lower battery cell 9).

[0036] S5: Apply adhesive to the upper surface of the lower cell 9, and then bond the cell aerogel 6 to the coated cell 9. After bonding, apply adhesive to the surface of the cell aerogel 6.

[0037] S6: Place the battery cell 9 flat on the coated aerogel 6 according to the required positive and negative electrode arrangement (upper battery cell 9).

[0038] S7: Apply adhesive to the upper surface of the upper cell 9. After completion, bond the first epoxy board 4 to the cell 9. After bonding, apply adhesive to the surface of the first epoxy board 4.

[0039] S8: Align the tray 1 with the first epoxy board 4 after applying adhesive and bond it to the position.

[0040] S9: Remove the adhesive backing of the second epoxy board 5 and attach it to the inner surface of the right sheet metal panel 2 and the left sheet metal panel 3.

[0041] S10: Secure the disassembled sheet metal right panel 2 and sheet metal left panel 3 with M5 hexagonal flange nuts 17 and M5x12 rivet screws 19.

[0042] S11: Use M4*8 Phillips countersunk screws 16 to fix the busbar bracket 14 to the countersunk screw holes 22 on the disassembled tray 1.

[0043] S12: Connect the first aluminum busbar 11, the second aluminum busbar 12, and the third aluminum busbar 13 through the busbar slot 30 on the busbar bracket 1.

[0044] S13: Using a laser welding machine, the first aluminum busbar 11, the second aluminum busbar 12, and the third aluminum busbar 13 are laser welded to the positive and negative terminals of the battery cell 9 through the aluminum busbar welding surface 33.

[0045] S14: Wiring the 1P8S module acquisition harness assembly 10 through the busbar bracket cable tray 29 on the busbar bracket 14, and using M4 hexagonal flange nuts 15 to fix and mark the voltage acquisition OT terminals 34 and temperature acquisition OT terminals 35 on the harness branches to the M4x10 rivet screws 32 on the first aluminum busbar 11, the second aluminum busbar 12, and the third aluminum busbar 13.

[0046] S15: Peel off the second insulating film 8 and stick it to the bottom of the packaged battery cell 9, keeping it flush.

[0047] S16: Module label 24 is affixed to the required area on tray 1.

[0048] S17: Use M4x10 plastic screws 23 to snap together through the top insulating film rivet fixing hole 21 on the first insulating film 7 and the bus bracket M4 rivet hole 28 on the top insulating film rivet fixing hole 21.

[0049] S18: Lithium-ion module assembly 25 is hoisted through module hoisting hole 20 on tray 1.

[0050] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A flat-lying prismatic lithium-ion battery module, characterized in that: It includes an outer casing and multiple battery cells arranged in a flat manner inside the outer casing. The outer casing includes two trays and a sheet metal right panel and a sheet metal left panel connected to the two ends of the trays respectively. All battery cells are arranged in multiple layers. The two trays are distributed above and below the battery cells. The battery cell terminals and explosion-proof valves on the battery cells are in a horizontal state and located between the two trays.

2. The flat-lying prismatic lithium-ion battery module according to claim 1, characterized in that: Intercellular aerogel is disposed between the battery cells.

3. The flat-lying prismatic lithium-ion battery module according to claim 1, characterized in that: A first epoxy board is disposed between the tray and the battery cell, and a second epoxy board is disposed between the battery cell and the right and left panels of the sheet metal.

4. The flat-lying prismatic lithium-ion battery module according to any one of claims 1 to 3, characterized in that: The battery cell has a first insulating film and a second insulating film distributed on both sides.

5. The flat-lying prismatic lithium-ion battery module according to claim 4, characterized in that: The first insulating film and the second insulating film are PC insulating films.

6. The flat-lying prismatic lithium-ion battery module according to claim 4, characterized in that: A busbar support is provided between the first insulating film and the battery cell, and a first aluminum busbar, a second aluminum busbar and a third aluminum busbar are provided on the busbar support.

7. The flat-lying prismatic lithium-ion battery module according to claim 6, characterized in that: The first aluminum busbar, the second aluminum busbar, and the third aluminum busbar are snapped onto the busbar bracket.

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