Square-shell lithium ion battery module

Abstract

The utility model discloses a square shell lithium ion battery module which comprises a battery cell stacking structure, two aluminum end plates arranged at the two ends of the battery cell stacking structure, a first strapping tape and a second strapping tape, the first strapping tape and the second strapping tape are used for strapping and fixing the battery cell stacking structure and the aluminum end plates, and the first strapping tape is made of PET plastic steel tape. The second strapping tape is made of stainless steel, and compressed silicon rubber is arranged between the battery core stacking structure and the aluminum end plate. The square shell lithium ion battery module disclosed by the utility model is simple in structural design and convenient in assembly and repair processes, and structural parts can be reduced and optimized on the basis of meeting the product reliability.

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 square-shell lithium-ion battery module. Background Technology

[0002] Currently, most new energy vehicle power batteries use lithium-ion batteries, which offer better safety performance and cost advantages.

[0003] Currently, the prismatic lithium-ion battery packs mainly adopt a vertical stacking method for the cells, with buffer pads supporting the large surfaces of the cells. They are wrapped by welding aluminum end plates and side plates, resulting in high overall structural strength. However, the welding equipment for the module end plates and side plates requires high precision. If a problem occurs with a cell in the module, rework is extremely difficult and in most cases, it will lead to the scrapping of the entire module. In addition, because the cells are wrapped by aluminum sheet metal end plates, the overall heat dissipation performance is poor, and the insulation performance of the module is required to be high. The blue film of the module cells cannot be damaged, and the aluminum end plates and side plates also need to be covered with an insulation film. If the insulation film is damaged, it will lead to poor insulation and, in severe cases, the scrapping of the module.

[0004] Currently, for high-voltage connections and low-voltage data acquisition in modular battery cells, a higher degree of integration is often achieved by using an aluminum foil bar, an FPC (flexible printed circuit board), and a molded carrier to form a CCS (Cells Contact System) assembly. The CCS assembly has high overall integrity, and the welding process during module welding requires stringent standards. If the aluminum foil bar is over-welded, burn-through, or the FPC wire is broken, it cannot be repaired and must be reworked and the CCS welding operation repeated. This places extremely high demands on production process control and after-sales quality. In addition, during the cycle of use, the expansion and deformation of the prismatic battery cell will increase. Due to the design characteristics of the FPC, its resistance to cell deformation is limited, and there is a risk that the FPC body or the circuit of the welding point may be pulled and broken. The current mainstream battery cell temperature acquisition is more reflected in the aluminum foil bar welded to the cell, usually using a nickel sheet welding method. Regardless of the acquisition method, it is impossible to completely acquire the true temperature of the battery cell. More often, it relies on experiments and temperature field simulations to acquire temperature compensation software.

[0005] Chinese Patent Application No. 202023164102.7 discloses a square lithium-ion battery module assembly structure, which mainly includes several batteries (1). A plastic insulating sheet I (4) is provided between every two batteries (1), and the plastic insulating sheet I (4) bonds adjacent batteries (1) together. A battery connection device is provided between every two batteries (1), and the battery connection device connects several batteries (1) together in series. After the several batteries (1) are bonded by the plastic insulating sheet I (4) and connected in series by the battery connection device, they are arranged to form a battery module. Plastic end plates I (2) and plastic end plates II (3) are provided on both sides of the battery module, and the battery module is fixed together with plastic end plates I (2) and plastic end plates II (3). This utility model can not only adapt to different battery installation spaces, but also has a simple structure, is easy to install, and has low manufacturing cost.

[0006] The aim is to provide an improved prismatic lithium-ion battery module, particularly regarding the reduction and optimization of structural components while maintaining product reliability. 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 prismatic lithium-ion battery module, with the goal of reducing and optimizing structural components while ensuring product reliability.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a square-shell lithium-ion battery module, including a cell stacking structure, two aluminum end plates disposed at both ends of the cell stacking structure, and a first and a second binding strap for binding and fixing the cell stacking structure and the aluminum end plates. The first binding strap is made of PET plastic steel tape, the second binding strap is made of stainless steel, and compressed silicone rubber is disposed between the cell stacking structure and the aluminum end plates.

[0009] An end-plate side insulating film is provided between the cell stacking structure and the compressed silicone rubber.

[0010] The side surface of the cell stacking structure is provided with a cell side insulating film, and the bottom surface of the cell stacking structure is provided with a cell bottom insulating film.

[0011] The aluminum end plate is provided with an output electrode base mating groove for assembling the output electrode base assembly, an output electrode base I-shaped nut insert for connecting, fixing and protecting the output electrode, and an output electrode base protective cover.

[0012] The aluminum end plate is provided with module lifting holes and module end plate fixing holes.

[0013] The top surface of the battery cell stacking structure is provided with a busbar support, and a top insulating film cover plate is provided on the busbar support. The thickness of the top insulating film cover plate is 0.5mm.

[0014] The top insulating film cover is made of insulating and flame-retardant polycarbonate insulating film.

[0015] The busbar bracket is equipped with a module acquisition harness assembly, which includes a voltage acquisition point for acquiring cell voltage values ​​and a temperature acquisition point for acquiring cell temperature values.

[0016] A temperature switch for collecting temperature values ​​is installed on the top insulating film cover plate, and the temperature switch is electrically connected to the temperature switch wiring harness.

[0017] The top insulating film cover is equipped with a nameplate label, a positive electrode marking, and a negative electrode marking.

[0018] This utility model presents a square-shell lithium-ion battery module with a simple structural design, convenient assembly and repair process, and the ability to reduce and optimize structural components while meeting product reliability requirements. Attached Figure Description

[0019] This manual includes the following figures, which illustrate the following:

[0020] Figure 1 This is a schematic diagram of the overall external structure of a square-shell lithium-ion battery module according to this utility model;

[0021] Figure 2 This is a schematic diagram of the overall exploded structure of a square-shell lithium-ion battery module according to this utility model;

[0022] Figure 3 This is a schematic diagram of a square-shell lithium-ion battery module cell stacking structure according to the present invention;

[0023] Figure 4 This is a schematic diagram of the end plate and steel strip structure of a square-shell lithium-ion battery module according to this utility model;

[0024] Figure 5 This is a schematic diagram of a square-shell lithium-ion battery module busbar bracket and connecting busbar structure according to the present invention;

[0025] Figure 6 This is a schematic diagram of the data acquisition harness structure of a square-shell lithium-ion battery module according to this utility model;

[0026] Figure 7 This is a schematic diagram of the structure of a square-shell lithium-ion battery module CCS component according to this utility model;

[0027] Figure 8 This is a schematic diagram of a temperature switch and wiring harness for a square-shell lithium-ion battery module according to this utility model.

[0028] Figure 9 This is a schematic diagram of the insulating protective component for a square-shell lithium-ion battery module according to this utility model. Detailed Implementation

[0029] 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.

[0030] like Figures 1 to 9 As shown, this utility model provides a square-shell lithium-ion battery module, including a cell stacking structure, two aluminum end plates 4 disposed at both ends of the cell stacking structure, and a first binding strap 6 and a second binding strap 7 for binding and fixing the cell stacking structure and the aluminum end plates 4. The first binding strap 6 is made of PET plastic steel strapping, and the second binding strap 7 is made of stainless steel. A compression silicone rubber 17 is disposed between the cell stacking structure and the aluminum end plates 4. The cell stacking structure is composed of multiple cells 21 stacked together.

[0031] Specifically, in this utility model, a combination of stainless steel strip and plastic steel strip, along with compressed silicone foam and two-component polyurethane structural adhesive, replaces the traditional module structure (laser welding of aluminum module end side plates, use of compressed foam to fill between single sides of the battery cells, and use of structural adhesive to bond the narrow side of the battery cells to the side plates). The side plates (with insulating film covering) are eliminated, and the bottom and sides of the module are protected by ultra-thin PC insulating film adhesive bonding. This greatly reduces procurement and production costs and the high requirements for end side plate welding equipment, while improving the overall heat dissipation and insulation performance of the module. The CCS module adopts a distributed assembly method, using aluminum busbars, wire harnesses, and plastic carriers for separate packaging. During module welding, aluminum busbars and wire harnesses can be replaced or repaired individually. Due to the design characteristics of FPC, its resistance to cell deformation is limited, posing a risk of breakage from the FPC body or welded circuitry. The length of the wire harness acquisition points and main body is designed with extra allowance to mitigate the impact of module expansion and deformation on the acquisition wires after repeated use. Furthermore, the cell voltage and temperature acquisition points are secured with standard components, ensuring reliable connections and avoiding the serious risk of power interruption due to poor welding caused by welding methods. A separate temperature acquisition point is added to collect the actual temperature of the cell cover plate plus the cell aluminum busbar temperature, ensuring that the temperature is not affected by aluminum busbar temperature acquisition deviations. Simultaneously, the temperature switch, in conjunction with the control system, can quickly disconnect and protect the system in case of abnormalities. The top insulating film cover is fixed with 0.5mm PC (insulating and flame-retardant polycarbonate) insulating film, ensuring insulation protection while effectively reducing production costs and meeting the module's lightweight requirements.

[0032] like Figure 1As shown, a schematic diagram of the overall external structure of a square-shell lithium-ion battery module is provided. The square-shell lithium-ion battery module includes a nameplate label 11 for identifying and tracing the 1P16S module assembly 2; a positive electrode marker 12 and a negative electrode marker 13 for distinguishing the positive and negative electrode positions, the positive electrode marker 12 and the negative electrode marker 13 being disposed on a top insulating film cover plate; a first binding strap 6 and a second binding strap 7 for connecting the aluminum end plate 4, the battery cell 21, and the aluminum end plate 4; and a top insulating film cover plate 1 for insulating and protecting the battery cell 21 of the 1P16S module assembly 2. The bottom insulating film 3 of the battery cell is made of PC (insulating and flame-retardant polycarbonate) insulating film and has a thickness of 0.175mm; it includes M4*10 plastic rivets 10 for connecting the top insulating film cover 1 and the busbar bracket 18; it includes a module acquisition harness assembly 8 for acquiring module voltage and temperature; it includes an output pole base assembly 5 for fixing and supporting the output pole connection busbar; and it includes a temperature switch for acquiring the temperature of the top insulating film cover 1 and a temperature switch harness 9 connected to the temperature switch.

[0033] like Figure 1 and Figure 3 As shown, in this embodiment, two first strapping straps 6 are provided, and one second strapping strap 7 is provided. The second strapping strap 7 is located between the two first strapping straps 6. Three strapping strap limiting grooves 23 are provided on the aluminum end plate 4 to allow the first strapping strap 6 and the second strapping strap 7 to be embedded respectively, so as to prevent the strapping straps from moving.

[0034] like Figure 2 The diagram shows an exploded view of the external structure of a square-shell lithium-ion battery module. The module also includes a top insulating film cover 1, a bottom insulating film 3, an end-plate side insulating film 16, and a side insulating film 15 for external protection of the battery cell 21. The side insulating film 15 is made of PC (insulating and flame-retardant polycarbonate) and has a thickness of 0.175 mm. The module also includes a first binding strap 6 and a second binding strap 7 for binding the aluminum end plate 4, compressed silicone rubber 17, end-plate side insulating film 16, and the battery cells 21 by compression and stacking. The assembly includes two parallel aluminum end plates 4 surrounding the 7, with all battery cells 21 sandwiched between the two aluminum end plates 4; it includes a module acquisition harness assembly 8 and a temperature switch harness 9 for voltage and temperature acquisition of the 1P16S module assembly 2; it includes M4*10 plastic rivets 10 for fixing the top insulating film cover 1 and busbar bracket 18; it includes an output pole base assembly 5 and an M6*16 hexagonal head assembly 19 for fixing the first aluminum busbar 33 and the third aluminum busbar 35; and it includes a nameplate label 11, a positive pole label 12, and a negative pole label 13 for indicating the traceability and positive and negative pole identification of the 1P16S module assembly 2.

[0035] like Figure 3As shown, a schematic diagram of a prismatic lithium-ion battery module cell stacking structure is provided. The prismatic lithium-ion battery module also includes a positive electrode post 28 and a negative electrode post 29 for the positive and negative electrode output of the cell 21; a cell explosion-proof valve 27 for pressure relief protection when the cell 21 is abnormal; and a cell large surface 26 for applying adhesive and extruding the cells 21 in the stacking direction.

[0036] like Figure 4 As shown, a schematic diagram of a square-shell lithium-ion battery module end plate and steel strip structure is provided. The square-shell lithium-ion battery module also includes an aluminum end plate 4, a first binding strap 6, and a second binding strap 7 for extruding and bundling the 1P16S module assembly 2; an output electrode base mating groove 25 for assembling the output electrode base assembly 5, and an output electrode base I-nut insert 20 and an output electrode base protective cover 30 for connecting, fixing, and protecting the output electrode; a module lifting hole 24 and a module end plate fixing hole 31 for lifting and fixing the 1P16S module assembly 2; and a module end plate cell surface 32 for the glued contact surface between the battery cell 21 of the 1P16S module assembly 2 and the aluminum end plate 4.

[0037] like Figure 5 , Figure 7 As shown, a schematic diagram of a busbar bracket and connecting structure for a square-shell lithium-ion battery module, and a schematic diagram of a CCS component structure for a square-shell lithium-ion battery module are provided. The square-shell lithium-ion battery module also includes a busbar bracket cover fixing hole 38 and an M4*10 plastic rivet 10 on the busbar bracket 18 for the top insulating film cover 1; a wire harness slot 36 for fixing the routing of the module acquisition wire harness assembly 8 and the temperature switch wire harness 9; and aluminum busbars for locking and limiting the first aluminum busbar 33, the second aluminum busbar 34, and the third aluminum busbar 35. The slot 41 includes an aluminum busbar fixing hole 39 for fixing the output electrode aluminum busbar and an M6*16 hexagonal head assembly 19; an aluminum busbar welding surface 40 for welding the first aluminum busbar 33, the second aluminum busbar 34, the third aluminum busbar 35 and the battery cell 21; an M4*10 press-fit screw 37 and an M4 hexagonal flange nut 44 for fixing the voltage acquisition point 42 and temperature acquisition point 43 of the module acquisition harness assembly 8; and a busbar bracket temperature harness through hole 45 on the busbar bracket 18 for the output of the temperature switch harness 9.

[0038] like Figure 6 , Figure 8 As shown, a schematic diagram of a square-shell lithium-ion battery module acquisition harness structure and a schematic diagram of a square-shell lithium-ion battery module temperature switch and harness are provided. The structure mainly includes voltage acquisition point 42 and temperature acquisition point 43 for sampling of the module acquisition harness assembly 8; and temperature switch 46 and temperature switch harness 9 for acquiring the temperature of the upper cover plate of the cell 21.

[0039] like Figure 9As shown, a schematic diagram of a square-shell lithium-ion battery module acquisition harness structure is provided. The structure mainly includes compressed silicone rubber 17 for compression buffering of the 1P16S module assembly 2; a top insulating film cover 1, a bottom insulating film 3, a side insulating film 15, and an end plate side insulating film 16 for insulating protection of the battery cell 21, aluminum end plate 4, and second binding strap 7; and a nameplate label 11, a positive electrode label 12, and a negative electrode label 13 for tracing the 1P16S module assembly 2 and identifying the positive and negative electrodes.

[0040] The above-described prismatic lithium-ion battery module has the following advantages:

[0041] The square-shell battery cells are stacked on their large surfaces, bonded together with a two-component polyurethane structural adhesive. This ensures the overall strength and rigidity of the assembled cells, meeting various operating conditions. An insulating film is added to the end plate sides for enhanced insulation and protection. Compressible silicone pads on both sides of the end plate meet the compressive pressure requirements of the assembled cells and absorb the influence of dimensional tolerances of the cells and other components on the assembly of the stainless steel strips and the positioning of the module fixing points. A combination of stainless steel strips and plastic-coated steel strips ensures the compressive pressure requirements after module stacking, as well as the expansion force and stress relaxation after cell cycle durability. The bottom and sides of the module are bonded with a 0.175mm ultra-thin PC insulating film, ensuring insulation protection for the module cells while minimizing the impact on cell heat dissipation. The insulating film provides insulation and scratch protection while facilitating replacement and repair. The CCS module assembly consists of an aluminum busbar, a wire harness, and a plastic carrier. The aluminum busbar is secured by clips on the plastic components and can be installed and removed independently. The wire harness is also secured by grooves on the plastic components and can be installed and removed independently. After the aluminum busbar is welded, the wire harness is fastened to the cell voltage and temperature acquisition points. The acquisition points are reliably installed, avoiding quality problems caused by poor welding or over-welding. The acquisition points can be installed and removed independently, and the length of the wire harness acquisition points and the main body of the wire harness is reserved to ensure that the expansion and deformation of the acquisition wires after repeated use do not affect the pulling effect of the acquisition wires. In addition to temperature acquisition on the aluminum busbar, a separate temperature acquisition point is added on the cell cover plate. Thermally conductive structural adhesive is used to completely adhere the contact surface of the temperature sensor to the cell cover plate, and the temperature wire harness is led out separately for independent acquisition, calibration, and control. This avoids the errors of acquisition only on the aluminum busbar and adds protection against temperature control disconnection.

[0042] like Figures 1 to 9 As shown, the assembly process of the above-described prismatic lithium-ion battery module includes the following steps:

[0043] S1: Take battery cell 21 and place it on the workbench according to the positive and negative requirements.

[0044] S2: Peel off the adhesive backing of the compressed silicone rubber 17 and stick it onto the module end plate cell surface 32 of the aluminum end plate 4 as required. Apply two-component polyurethane structural adhesive into the groove after pasting.

[0045] S4: Place the coated aluminum end plate 4 into the extrusion limiting fixture, and perform the end plate side insulation film 16 pasting operation on the contact side of the first cell 21 with the cell surface 32 of the module end plate.

[0046] S5: Adhere the battery cell 21 with the insulating film 16 on the end plate to the aluminum end plate 4 with glue. Take the battery cell 21 and apply glue to it in sequence. Stack and bond the cells according to the placement order. Repeat the operation requirements of S2 and S4 for the last battery cell.

[0047] S6: The stacked modules are extruded by the tooling until the extrusion pressure or stroke reaches the operation requirements and the extrusion is stopped. The second strapping 7 is then put on the module until it stops at the strapping limit groove 23 on the aluminum end plate 4, and the tooling pressure is released.

[0048] S7: Remove the adhesive backing from the insulating film 15 on the side of the battery cell and stick it to the side of the stacked length of the 2 battery cells in the 1P16S module assembly.

[0049] S8: After the module is flipped in the S7 process, remove the backing adhesive from the bottom insulating film 3 of the battery cell and attach protective adhesive to the bottom of the battery cell 21.

[0050] S9: After the module is flipped in the flipping process S8, take two first strapping straps 6 and place them in the strapping strap limiting grooves 23 on the aluminum end plate 4, and use a hot melt packaging machine to pack and bundle them.

[0051] S10: Take the output electrode base assembly 5 and insert it into the output electrode base mating groove 25 on the aluminum end plate 4, and open the output electrode base protective cover 30 of the output electrode base assembly 5.

[0052] S11: Place the busbar bracket 18 on the 1P16S module assembly 2, and fix the first aluminum busbar 33, the second aluminum busbar 34, and the third aluminum busbar 35 through the aluminum busbar slot 41 on the busbar bracket 18.

[0053] S12: Take two M6*16 hexagonal head assemblies 19, and fix the first aluminum busbar 33 and the third aluminum busbar 35 to the output pole base I-shaped nut insert 20 on the output pole base assembly 5 through the aluminum busbar fixing hole 39.

[0054] S13: Using a laser welding machine, the first aluminum busbar 33, the second aluminum busbar 34, and the third aluminum busbar 35 are fixed and limited by the busbar bracket 18, and welding is performed on the aluminum busbar welding surface 40.

[0055] S14: The temperature switch 46 is bonded to the top cover of the battery cell 21 and the busbar bracket 18 using thermally conductive structural adhesive.

[0056] S15: Arrange and fix the module acquisition harness assembly 8 through the harness slot 36 on the busbar bracket 18.

[0057] S16: Use M4 hexagonal flange nuts 44 to fix the voltage acquisition point 42 and temperature acquisition point 43 on the module acquisition harness assembly 8 with M4*10 press-fit screws 37 on the first aluminum busbar 33, the second aluminum busbar 34 and the third aluminum busbar 35. After torque operation, confirm by painting.

[0058] S17: Connect one end of the temperature switch harness 9 to the terminal on the temperature switch 46, and pass the other end through the busbar bracket temperature harness through hole 45 on the busbar bracket 18.

[0059] S18: Use M4*10 plastic rivets 10 to snap into the busbar bracket cover plate fixing holes 38 on the busbar bracket 18 through the top insulating film cover plate fixing holes 14 on the top insulating film cover plate 1.

[0060] S19: Reinstall the output terminal base protective cover 30 back onto the output terminal base assembly 5.

[0061] S20: Affix the nameplate label 11 to the top insulating film cover plate 1 and the aluminum end plate 4 as required.

[0062] S21: Test the voltage, temperature, and internal resistance of 1P16S module assembly 2, and package and store it if it passes the test.

[0063] 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 square-shell lithium-ion battery module, characterized in that: The device includes a cell stacking structure, two aluminum end plates disposed at both ends of the cell stacking structure, and a first and a second binding strap for binding and fixing the cell stacking structure and the aluminum end plates. The first binding strap is made of PET plastic steel tape, and the second binding strap is made of stainless steel. Compressed silicone rubber is disposed between the cell stacking structure and the aluminum end plates.

2. The prismatic lithium-ion battery module according to claim 1, characterized in that: An end-plate side insulating film is provided between the cell stacking structure and the compressed silicone rubber.

3. The prismatic lithium-ion battery module according to claim 1, characterized in that: The side surface of the cell stacking structure is provided with a cell side insulating film, and the bottom surface of the cell stacking structure is provided with a cell bottom insulating film.

4. The prismatic lithium-ion battery module according to any one of claims 1 to 3, characterized in that: The aluminum end plate is provided with an output electrode base mating groove for assembling the output electrode base assembly, an output electrode base I-shaped nut insert for connecting, fixing and protecting the output electrode, and an output electrode base protective cover.

5. The prismatic lithium-ion battery module according to any one of claims 1 to 3, characterized in that: The aluminum end plate is provided with module lifting holes and module end plate fixing holes.

6. The prismatic lithium-ion battery module according to any one of claims 1 to 3, characterized in that: The top surface of the battery cell stacking structure is provided with a busbar support, and a top insulating film cover plate is provided on the busbar support. The thickness of the top insulating film cover plate is 0.5mm.

7. The prismatic lithium-ion battery module according to claim 6, characterized in that: The top insulating film cover is made of insulating and flame-retardant polycarbonate insulating film.

8. The prismatic lithium-ion battery module according to claim 6, characterized in that: The busbar bracket is equipped with a module acquisition harness assembly, which includes a voltage acquisition point for acquiring cell voltage values ​​and a temperature acquisition point for acquiring cell temperature values.

9. The prismatic lithium-ion battery module according to claim 6, characterized in that: A temperature switch for collecting temperature values ​​is installed on the top insulating film cover plate, and the temperature switch is electrically connected to the temperature switch wiring harness.

10. The prismatic lithium-ion battery module according to claim 6, characterized in that: The top insulating film cover is equipped with a nameplate label, a positive electrode marking, and a negative electrode marking.

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