A secondary repairable soft-package battery module structure and assembly and disassembly method

Abstract

A soft-package battery module structure that can be repaired twice and an assembly and disassembly method can solve the technical problems that battery cells are difficult to reuse and the internal circulation performance of the cells is low. It includes a conductive spring inserted into the pole ear of the battery cell body, and a fixed bracket installed on the positive terminal or negative terminal of the battery cell body; end plates are arranged in parallel at both ends of the battery cell body, and a heat conduction plate is fixed at the bottom of the two end plates; large wedge blocks are inserted into the wedge holes of the fixed bracket in turn; small wedge blocks are wedged into one end of the large wedge block in turn, and wedged into the fixed bracket, so that the large wedge block is wedged into a fixed position; the conductive plate between the battery cells is placed between the battery cell bodies, tightly attached to the conductive spring and fixed. The present invention utilizes the effect of wedge force to improve the reliability of mechanical contact conduction and the large current conductivity, avoids series and parallel connection due to welding pole ears, and solves the problem of secondary repair and sorting of battery cells for reuse; in addition, it is convenient for the battery system to disassemble and maintain a single battery cell, reducing customer maintenance costs.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy storage batteries, and in particular to a secondary repairable soft-package battery module structure and an assembly and disassembly method. Background Art

[0002] Power lithium-ion batteries have been promoted and applied as an energy storage device in pure electric vehicles. When the battery system decays to a certain extent, according to regulations, when the energy of a general battery system decays to 70% or 80% of the original, it is not enough to support the effective mileage of the car, and the battery system will be retired, but there is still 10% or 20% or more of the energy use value. Since both soft-packaged batteries and square batteries currently use positive and negative electrode welding to form the battery system, non-destructive disassembly cannot be achieved, so that the battery cannot be reused at the battery cell level; in addition, the decay of battery life is mostly due to the relative drying of the electrolyte inside the battery cell caused by the expansion of the pole piece and the reaction of the electrolyte during the cycle, which causes the decay of cycle performance. Summary of the invention

[0003] The invention provides a secondary repairable soft-package battery module structure and an assembly and disassembly method, which can solve the technical problems that existing battery cells are difficult to reuse and the internal cycle performance of the cells is low.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A secondary repairable soft-package battery module structure, comprising:

[0006] The battery cell body includes a positive electrode and a negative electrode.

[0007] It also includes a small wedge block, a large wedge block, a conductive spring, a fixing bracket, a heat conducting plate, a battery pack cover, and a conductive plate for connecting between battery cells;

[0008] The conductive spring sheet is inserted into the tab of the battery cell body, and the fixing bracket is installed on the positive terminal or the negative terminal of the battery cell body;

[0009] End plates are arranged in parallel at both ends of the battery body, including end plate 1 and end plate 2, and the end plate 1, end plate 2 and a fixing bracket are fixed in sequence to form a module;

[0010] It also includes a heat conducting plate, which is fixed to the bottom of the two end plates;

[0011] The large wedge-shaped blocks are inserted into the wedge-shaped holes of the fixed brackets in sequence;

[0012] The small wedge blocks are wedged into one end of the large wedge blocks in turn, and wedged into the fixed bracket, so that the large wedge blocks are wedged into the fixed position, and the conductive springs are tightly pressed onto the pole ears by the wedging force of the wedge blocks;

[0013] The conductive plate between the cells is placed between the cell bodies, tightly attached to the conductive spring sheet, and welded to the conductive spring sheet;

[0014] Align the airbags of the battery cells in the same direction and snap on the battery pack cover.

[0015] Furthermore,

[0016] The conductive spring is made by folding a copper foil into a "U" shape and then flattening it; the middle of the two layers of copper foil is inserted into the pole ear of the battery cell and is tightly attached to the pole ear under the pressure of the large wedge block.

[0017] Furthermore,

[0018] The conductive spring is made of a .-mm thick copper foil which is folded into a "U" shape and then flattened.

[0019] Furthermore,

[0020] In order to increase the contact area and ensure the conductive property, convex points are punched on the conductive spring sheet, and the convex points are in contact with the tabs.

[0021] Furthermore,

[0022] The diameter of the protrusions is .-mm and the number is - pieces.

[0023] Furthermore, the material of the small wedge-shaped block is aluminum and plastic;

[0024] The material of the large wedge-shaped block is metal aluminum, copper, or plastic;

[0025] The fixing bracket is made of plastic.

[0026] Furthermore, thermal grease or a thermal pad is applied between the heat conducting plate and the bottom surface of the battery cell body, which also serves as a vibration buffer.

[0027] Furthermore, the conductive plates and conductive springs between the battery cells are fixed by laser welding.

[0028] On the other hand, the present invention also discloses an assembly method of a soft-package battery module structure that can be repaired again, based on the above-mentioned soft-package battery module structure that can be repaired again, comprising the following steps:

[0029] 11) First insert the conductive spring into the lug of the battery cell body, then hit the fixing bracket against the positive end of the battery cell, and similarly the negative end to form a basic assembly unit. According to the series and parallel requirements, put the battery cell body, end plate 1, and end plate 2 together, and use bolts to pass through the holes on end plate 1, end plate 2, and fixing bracket in sequence. After forming the module, fix the heat conduction plate to the bottom of the two end plates, and apply thermal grease or thermal gasket between the heat conduction plate and the bottom surface of the battery cell body, which also plays a vibration buffering role;

[0030] 12) Insert the large wedge blocks into the wedge holes of the fixed bracket one by one;

[0031] 13) Then wedge the small wedge block into one end of the large wedge block in sequence, and wedge it into the fixed bracket, so that the large wedge block is wedged into the fixed position, and the conductive spring sheet is tightly pressed against the pole ear by the wedging force of the wedge block, so that the convex point on the conductive spring sheet is in close contact with the pole ear to play a role in conducting large current;

[0032] 14) Place the conductive plate between the battery cells, tightly attach it to the conductive spring sheet, and weld it to the conductive spring sheet by laser welding;

[0033] 15) Align the airbags of the battery cells in the same direction, close the battery pack cover, and complete the assembly of the battery module.

[0034] The present invention also discloses a method for disassembling a soft-package battery module structure that can be repaired again, which is also based on the soft-package battery module structure that can be repaired again.

[0035] The following steps are involved:

[0036] 21) Take out the small wedge-shaped block;

[0037] 22) Remove the wedging force of the large wedge block;

[0038] 23) Take out the conductive plate and conductive spring as a whole;

[0039] 24) Remove the battery pack cover and heat conducting plate;

[0040] 25) Loosen the fixing bolts, remove end plate 1 and end plate 2, and separate the battery body and other components;

[0041] 26) Remove the fixing bracket and store the battery cells separately.

[0042] It can be seen from the above technical solution that the second-repairable soft-package battery module structure of the present invention has the following beneficial effects:

[0043] Different from the traditional soft-package battery cells, the final sealing and folding process is cancelled, and the battery PACK structure with the airbag design during liquid injection is retained to facilitate the secondary final sealing after liquid replenishment; in the design of the PACK structure, the wedge force is used to improve the reliability of mechanical contact conductivity and the large current conductivity, avoid series and parallel connection due to welding of the pole ears, and solve the problem of secondary repair and sorting of the battery cells during reuse; in addition, it is convenient for the battery system to disassemble and maintain a single battery cell, reducing the customer's maintenance cost; 3. A packaging structure is proposed that breaks through the difficulty of the thickness limit of traditional battery cell packaging, is beneficial to the internal heat conduction of the battery cell, and improves the grouping rate of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the structure of the present invention;

[0045] Figure 2 It is a partial structural schematic diagram of the present invention;

[0046] Figure 3 It is a schematic diagram of the conductive spring structure of the present invention;

[0047] Figure 4 is a schematic diagram of the top view of the conductive spring of the present invention;

[0048] Figure 5 It is a schematic diagram of the internal structure of the present invention;

[0049] Figure 6 It is a schematic diagram of the side view of the heat conducting plate and the battery pack cover after being assembled according to the present invention;

[0050] Figure 7 It is a schematic diagram of the parallel combination of end plates of the present invention. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0052] Figure 1-Figure 7 The schematic diagram of the structure of the flexible package battery cell of the embodiment of the present invention is shown in which the tabs are connected when the battery cell is grouped into a PACK and the battery cell is fixed without welding. In order to illustrate this mechanism, the positive terminal structure is taken as an example, and the negative terminal structure is the same.

[0053] The structure is composed of a small wedge block 1, a large wedge block 2, a conductive spring 3, and a fixed bracket 4. Among them, the conductive spring 3 is as follows Figure 3As shown, it is made of 0.3-1 mm thick copper foil folded into a "U" shape and then flattened. The middle of the two layers of copper foil is inserted into the pole ear 5 of the battery cell 6. Under the pressure of the large wedge block 2, it is tightly close to the pole ear 5. In order to increase the contact area and ensure the conductive properties, convex points are stamped on it, and the convex points are in contact with the pole ear 5. The diameter of the convex points is 0.5-3 mm, and the number is 50-150. The material of the small wedge block 1 can be aluminum, plastic, etc., the material of the large wedge block 2 can be metal aluminum, copper, plastic, etc., and the material of the fixing bracket 4 is plastic, etc.

[0054] like Figure 5 , 6 , 7 show the battery pack structure of an embodiment. It is composed of a small wedge block 1, a large wedge block 2, a conductive spring 3, a fixing bracket 4, a battery cell 6, a heat conducting plate 7, a battery pack cover 8, an end plate 9, an end plate 10, a conductive plate 11 connecting the battery cells, and 4 long bolts for connection and fixing.

[0055] The assembly sequence and functions are as follows:

[0056] 1. First, insert the conductive spring 3 into the tab 5 of the battery cell 6, and then push the fixing bracket 4 into the positive terminal of the battery cell. The same structure is applied to the negative terminal. The basic assembly unit is formed. According to the series and parallel requirements, the battery cells, end plates 9 and 10 are placed in parallel. Figure 7 As shown, bolts are sequentially passed through the holes on the end plates 9, 10 and the fixing bracket 4 to form a module, and then the heat conducting plate 7 is fixed to the bottom of the two end plates. Thermal grease or thermal conductive pads are applied between the heat conducting plate 7 and the bottom surface of the battery cell 6, which also plays a role in vibration buffering.

[0057] 2. Insert the large wedge-shaped blocks 2 into the wedge-shaped holes of the fixed bracket 4 in sequence;

[0058] 3. Then, the small wedge block 1 is wedged into one end of the large wedge block 2 and into the fixed bracket 4, so that the large wedge block 2 is wedged into a fixed position, and the conductive spring sheet 3 is tightly pressed against the pole ear 5 by the wedging force of the wedge block, so that the convex point on the conductive spring sheet 3 is in close contact with the pole ear 5 to play a role in conducting large current;

[0059] 4. Place the conductive plate 11 between the battery cells 6, tightly attach it to the conductive spring sheet 3, and weld it to the conductive spring sheet 3 by laser welding;

[0060] 5. Arrange the airbags of the battery cells in the same direction and put on the battery pack cover 8 to complete the assembly of the battery module of the present invention.

[0061] At the same time, after the battery pack of the embodiment of the present invention completes the first stage of service life, it is retired to the stage of cascade utilization. The battery pack can be disassembled in the following order:

[0062] (1) Take out the small wedge block 1, (2) Remove the wedging force of the large wedge block 2, (3) Take out the conductive plate 11 and the conductive spring 3 as a whole, (4) Remove the battery pack cover 8 and the heat conducting plate 7, (5) Loosen the fixing bolts, remove the end plates 9 and 10, separate the battery cell 6 and other components, (6) Remove the fixing bracket 4, and store the battery cells 6 separately. The battery cells 6 can then be repaired or reused.

[0063] The repair method of the battery cell structure of the embodiment of the present invention. The battery cell 6 is charged and discharged, divided into capacities and groups, and then discharged to a cut-off voltage of 2.75 or to a cut-off voltage value that theoretically does not damage the battery. Then, the cells are divided into groups and filled with liquid on a special liquid filling machine, sealed, and placed aside, and then divided into capacities, and then reassembled and used according to the method of the present invention.

[0064] As can be seen from the above, the original assembly manufacturing process is stacking - welding - packaging (packaging film forming - top sealing - side seam) - drying - liquid injection - pre-sealing - chemical formation - primary sealing - cutting airbags - fine sealing - folding - volume separation - aging - storage;

[0065] The process of the structural battery cell of the embodiment of the present invention is: lamination - welding - packaging (top sealing - side sealing) - drying - liquid injection - pre-sealing - formation - final sealing by vacuuming (keeping the air bag as large as possible) - shaping - capacity division - aging - storage. The difference is that the air bag after formation is kept in the assembly process.

[0066] In summary, the embodiments of the present invention solve the problem that the tabs of soft-packaged cells are welded to the busbars when they are grouped, resulting in permanent fixation, which makes it impossible to implement cell-level utilization during cascade utilization. At the same time, a new cell structure and assembly process are adopted to solve the heat conduction at the bottom of the soft-packaged cells and the rehydration function before cascade utilization, thereby extending the number of cycles of cascade utilization. The pack structure of the embodiments of the present invention is applicable to all soft-packaged cells with thin-sheet tabs.

[0067] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A secondary repairable soft-package battery module structure, comprising a battery cell body (6), the battery cell body (6) comprising a positive electrode and a negative electrode, characterized in that: It also includes a small wedge-shaped block (1), a large wedge-shaped block (2), a conductive spring (3), a fixing bracket (4), a heat-conducting plate (7), a battery pack cover (8), and a conductive plate (11) for connecting between battery cells; The conductive spring sheet (3) is inserted into the tab (5) of the battery cell body (6), and the fixing bracket (4) is installed on the positive terminal or the negative terminal of the battery cell body (6); End plates are arranged in parallel at both ends of the battery cell body (6), including an end plate 1 (9) and an end plate 2 (10), wherein the end plate 1 (9), the end plate 2 (10) and the fixing bracket (4) are fixed in sequence to form a module; It also includes a heat conducting plate (7), which is fixed to the bottom of the two end plates; The large wedge-shaped blocks (2) are sequentially inserted into the wedge-shaped holes of the fixed brackets (4); The small wedge blocks (1) are sequentially wedged into one end of the large wedge block (2) and into the fixed bracket (4), so that the large wedge block (2) is wedged into a fixed position, and the conductive spring sheet (3) is tightly pressed onto the pole ear (5) by the wedging force of the wedge blocks; The conductive plate (11) between the battery cells is placed between the battery cell bodies (6), tightly attached to the conductive spring sheet (3), and welded to the conductive spring sheet (3); Arrange the air bags of the battery cells in the same direction and put on the battery pack cover (8); Thermal grease or a thermal pad is applied between the heat conducting plate (7) and the bottom surface of the battery cell body (6), which also serves as a vibration buffer; The conductive spring sheet (3) is made by folding a copper foil into a "U" shape and then flattening it; the middle of the two layers of copper foil is inserted into the pole ear of the battery cell and is tightly attached to the pole ear under the pressure of the large wedge block (2).

2. The secondary repairable soft-package battery module structure according to claim 1, characterized in that: The conductive spring sheet (3) is made of a copper foil material with a thickness of 0.3-1 mm which is folded into a "U" shape and then flattened.

3. The secondary repairable soft-package battery module structure according to claim 1, characterized in that: A convex point is punched on the conductive spring sheet (3), and the convex point is in contact with the tab (5).

4. The secondary repairable soft-package battery module structure according to claim 3 is characterized in that: The diameter of the protrusions is 0.5-3 mm, and the number is 50-150.

5. The secondary repairable soft-package battery module structure according to claim 1, characterized in that: The conductive plates (11) between the battery cells and the conductive spring sheets (3) are fixed by laser welding.

6. A method for assembling a repairable soft-package battery module structure, based on the repairable soft-package battery module structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: 11) First, insert the conductive spring sheet (3) into the tab (5) of the battery cell body (6), and then install the fixing bracket (4) to the positive terminal of the battery cell. Similarly, the negative terminal has the same structure to form a basic assembly unit. According to the series and parallel requirements, the battery cell body (6), end plate one (9), and end plate two (10) are arranged in parallel. Bolts are passed through the holes on the end plate one (9), end plate two (10), and fixing bracket (4) in sequence to form a module. After the module is formed, the heat conducting plate (7) is fixed to the bottom of the two end plates. Thermal grease or thermal conductive gasket is applied between the heat conducting plate (7) and the bottom surface of the battery cell body (6), which also acts as a vibration buffer. 12) Insert the large wedge-shaped blocks (2) into the wedge-shaped holes of the fixed bracket (4) one by one; 13) The small wedge block (1) is then wedged into one end of the large wedge block (2) and into the fixed bracket (4) in sequence, so that the large wedge block (2) is wedged into a fixed position, and the conductive spring sheet (3) is tightly pressed onto the pole ear (5) by the wedging force of the wedge block, so that the convex point on the conductive spring sheet (3) is in tight contact with the pole ear (5) to play a role in conducting a large current; 14) placing the conductive plate (11) between the battery cell bodies (6), tightly attached to the conductive spring sheet (3), and welding the conductive spring sheet (3) together by laser welding; 15) Align the airbags of the battery cells in the same direction and fasten the battery pack cover (8) to complete the assembly of the battery module.

7. A method for disassembling a repairable soft-package battery module structure, based on the repairable soft-package battery module structure according to any one of claims 1 to 5, characterized in that: The following steps are involved: 21) Take out the small wedge (1); 22) Remove the wedging force of the large wedge block (2); 23) Remove the conductive plate (11) and the conductive spring (3) as a whole; 24) Remove the battery pack cover (8) and heat conducting plate (7); 25) Loosen the fixing bolts, remove the end plate 1 (9) and the end plate 2 (10), and separate the battery cell body (6) and other components; 26) Remove the fixing bracket (4) and store the battery cell body (6) separately.

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