An energy storage device for secondary use of old batteries

Abstract

This utility model relates to the field of power battery recycling and reuse technology, and discloses an energy storage device for the secondary utilization of old batteries, including a cell box and a cell assembly within the cell box; the cell assembly includes M*N cells, which are welded together with nickel sheets to form a large cell. The nickel sheets include vertical nickel sheets for series connection and oblique nickel sheets for parallel connection, and the vertical nickel sheets are connected by the oblique nickel sheets; an upper protection plate and a lower protection plate are respectively provided at the upper and lower ends of the large cell, and a base plate is provided below the lower protection plate, with a BMS plate between the lower protection plate and the base plate; a side frame is provided on the outer side of the large cell, the side frame is "U" shaped, the upper part of the side frame is connected to the upper protection plate, and the lower part of the side frame is connected to the base plate. This utility model can solve the problem of old batteries not being fully utilized in the prior art, resulting in resource waste.

Description

Technical Field

[0001] This utility model relates to the field of power battery recycling and reuse technology, specifically to an energy storage device for the secondary use of old batteries. Background Technology

[0002] With the rapid development of the new energy industry, the widespread application of battery technology has led to a dramatic increase in the use of battery packs in various projects. During this process, with technological advancements and equipment upgrades, projects are increasingly facing replacement or abandonment due to substandard battery pack performance or localized defects. However, among these replaced or abandoned battery packs, there are often a large number of older batteries with intact individual cells, whose capacity retention rate can generally reach over 80%, still possessing significant usability.

[0003] Currently, there are obvious shortcomings in the traditional methods of handling these old batteries. The common practice is to directly discard the entire battery pack or simply seal it up and leave it unattended. Neither of these methods fully considers the reuse value of the old batteries that still have high performance, resulting in the following problems: (1) Occupying storage space: The idleness of a large number of old batteries occupies a lot of valuable storage space, which greatly increases the cost of inventory management; (2) Serious waste of resources: The production of each battery is accompanied by the consumption of raw materials and energy. The simple idleness of a large number of reusable batteries without effective treatment is undoubtedly a great waste of resources, which is not in line with the development concept of circular economy and exacerbates the resource shortage situation; (3) Environmental impact: If the waste batteries are not properly handled, they will cause potential pollution to the environment. Utility Model Content

[0004] The present invention aims to provide an energy storage device for the secondary utilization of old batteries, in order to solve the problem that old batteries cannot be fully utilized in the prior art, resulting in resource waste.

[0005] To achieve the above objectives, this utility model adopts the following technical solution: It includes a cell box and a cell assembly within the cell box; the cell assembly includes M*N cells, which are welded together to form a large cell using nickel sheets. The nickel sheets include vertical nickel sheets for parallel connection and oblique nickel sheets for series connection, with the vertical nickel sheets connected to each other via the oblique nickel sheets; the large cell has an upper protection plate and a lower protection plate at its upper and lower ends respectively, a substrate is provided below the lower protection plate, and a BMS board is provided between the lower protection plate and the substrate; a side frame is provided on the outer side of the large cell, the side frame being "U"-shaped, with the upper part of the side frame connected to the upper protection plate and the lower part of the side frame connected to the substrate.

[0006] The principle of this solution is as follows: In practical applications, standard-compliant old battery cells are selected from the inventory (i.e., old batteries) to ensure their performance and safety meet the requirements for reuse. The selected cells are then combined in an M*N arrangement to form a cell group. Specifically, several cells are connected by welding nickel sheets to form a large cell. These nickel sheets include vertical and diagonal nickel sheets. The vertical nickel sheets are connected by diagonal nickel sheets, which are used to connect cells in parallel to increase cell capacity. The diagonal nickel sheets are used to connect cells in series to increase the voltage and energy requirements of a single large cell. Finally, a protection plate and a lower protection plate are welded to the top and bottom ends of the large cell to enhance its stability. Secondly, a substrate is installed below the lower protective plate, and a BMS board is placed between the lower protective plate and the substrate to monitor the operating status of the large battery cell. Finally, a "U"-shaped side frame is installed on the outside of the large battery cell. The upper part of the side frame is connected to the upper protective plate, and the lower part of the side frame is connected to the substrate, thus forming the battery cell assembly. The side frame provides mechanical protection, enhances the stability of the overall structure, and effectively reduces the impact of external shocks or vibrations on the battery cell assembly. After the battery cell assembly is completed, it is placed in a battery cell box to form a complete energy storage device.

[0007] The advantages of this scheme are: (1) This scheme breaks the technical prejudice that "old battery cells cannot be reused". In the traditional view, old battery cells are usually considered unsuitable for reuse due to performance degradation and potential safety hazards, and are often directly discarded or shelved. However, this scheme forms a new energy storage device by rearranging old battery cells, realizing the secondary use of old battery cells, thereby reducing resource waste.

[0008] (2) In this scheme, old batteries are reassembled to form an energy storage device, which realizes the effective reuse of resources. This not only reduces the environmental impact of old batteries, but also avoids the stacking of inventory to a certain extent and reduces inventory management costs.

[0009] (3) In this scheme, the upper and lower protection plates play a protective role, provide mechanical support, enhance the overall stability and mechanical strength of the large battery cell assembly, and ensure that it is not easily damaged during transportation and use.

[0010] (4) The connection between the cells is made by combining vertical and oblique nickel plates, which not only increases the cell capacity, but also improves the voltage and energy requirements.

[0011] (5) The BMS board (i.e., the battery management system) is responsible for monitoring and managing the status of each cell, including parameters such as voltage, current, and temperature. The BMS board can adjust the charging and discharging process in real time to prevent overcharging, over-discharging, over-temperature and other problems, ensuring the safe operation of the battery pack and extending battery life.

[0012] (6)The "U-shaped" side frame plays a protective role, not only providing additional mechanical protection for the entire battery cell group, but also enhancing the stability of the overall structure and reducing the impact of external shocks on the battery cells.

[0013] Preferably, as an improvement, the battery cells are arranged in a staggered manner, and both M and N are integers greater than or equal to 2.

[0014] Beneficial effects: The staggered arrangement of the battery cells makes the distance between adjacent battery cells more uniform, avoiding the local overheating problem caused by close arrangement and enabling the heat to be evenly distributed in the battery cell group, thus improving the overall heat dissipation performance. Both M and N are integers greater than or equal to 2, which can flexibly adjust the number and arrangement of battery cells according to actual needs to adapt to energy storage devices of different sizes and capacities.

[0015] Preferably, as an improvement, the voltage difference between the battery cells ≤ 20mv, and the internal resistance difference ≤ 0.1mΩ.

[0016] Beneficial effects: Through the settings of the voltage difference and internal resistance difference, it is ensured that each battery cell performs consistently during charge and discharge, avoiding the imbalance problem caused by excessive performance differences of individual battery cells and improving the performance and reliability of the entire battery cell group.

[0017] Preferably, as an improvement, the angle between the vertical nickel sheet and the oblique nickel sheet is 40 - 50 degrees.

[0018] Beneficial effects: The reasonable angle design enables the nickel sheet to adapt to the layout of the staggered arrangement of battery cells, making the connection of the nickel sheet more stable and being able to better resist external vibration and impact during use, thereby enhancing the mechanical strength of the entire battery cell group.

[0019] Preferably, as an improvement, the length of the vertical nickel sheet is 120mm - 122mm, the width of the vertical nickel sheet is 19mm - 21mm, and the thickness of the vertical nickel sheet is 0.2mm - 0.5mm; the length of the oblique nickel sheet is 12mm - 15mm, the width of the oblique nickel sheet is 4mm - 6mm, and the thickness of the oblique nickel sheet is 0.2mm - 0.5mm.

[0020] Beneficial effects: The design of the length and width of the vertical nickel sheet and the oblique nickel sheet enhances the connection stability of the nickel sheet, making the nickel sheet not easy to loosen or fall off during long-term use, ensuring the stability and reliability of the electrical connection, and at the same time ensuring that the nickel sheet has sufficient insulation spacing, reducing the short-circuit risk caused by improper dimensions. The design of the thickness of the vertical nickel sheet and the oblique nickel sheet ensures that the nickel sheet has sufficient tensile and bending resistance capabilities, can withstand large mechanical stresses during use, and can also withstand a high current density, avoiding the fusing problem caused by excessive current.

[0021] Preferably, as an improvement, both the upper protection plate and the lower protection plate are high-voltage protection plates, and the thickness of both the upper protection plate and the lower protection plate is 30mm-33mm.

[0022] Beneficial effects: The high-voltage protection board can withstand high voltage, preventing the battery cells from being damaged by overvoltage or causing safety accidents. The thickness design of the upper and lower protection boards provides sufficient mechanical support for the battery cell assembly, preventing deformation or damage to the battery cell assembly due to external impact or pressure, thereby improving the stability of the battery cell assembly.

[0023] Preferably, as an improvement, the battery cell box includes a side plate, the side plate having a "U" shaped structure, the upper end of the side plate having a top plate, and the lower end of the side plate having a bottom plate.

[0024] Beneficial effects: The cell box provides physical protection for the internal cell assembly, enhancing the overall rigidity and stability of the entire cell assembly and preventing damage to the cells from external impacts, collisions, or drops.

[0025] Preferably, as an improvement, the cell box is tightly fitted to the cell assembly.

[0026] Beneficial effects: The tight fit design ensures that the battery pack is stable and stationary inside the battery box, reducing damage to the battery cells caused by shaking and collisions during use. At the same time, it reduces unnecessary gaps between the battery pack and the battery box, reducing the risk of short circuits caused by foreign objects entering.

[0027] Preferably, as an improvement, the nickel sheets at the upper and lower ends of the battery cell are staggered and welded.

[0028] Beneficial effects: The staggered welding method can better fix the position of the battery cells, prevent the cells from moving relative to each other during use, enhance the stability of the overall structure, and reduce the risk of short circuits between adjacent cells due to improper welding.

[0029] Preferably, as an improvement, the cross-sectional area of ​​the upper protection plate is larger than the lateral area of ​​the large battery cell.

[0030] Beneficial effects: The cross-sectional area of ​​the upper protection plate is larger than the lateral area of ​​the large battery cell, which allows the upper protection plate to completely cover or even extend beyond the edge of the battery cell, providing an additional protective layer that can prevent external impacts and collisions from directly affecting the battery cell and reduce the risk of battery cell damage.

[0031] The beneficial effects of this plan are: (1) This plan fully reuses old batteries in the inventory, effectively matches them for safe assembly based on the effective aging data, promotes a new pattern of green energy utilization, takes green energy as the core purpose, and clears inventory as the practical guide.

[0032] (2) In this scheme, from screening old cells that meet the standards to accurately matching and recombining them into new cell groups, and finally integrating them into the energy storage device, each step has been carefully designed and tested to ensure its safety and feasibility.

[0033] (3) This solution can avoid resource waste, effectively reuse old batteries, maximize resource utilization, and at the same time avoid inventory accumulation to a certain extent, effectively avoiding cost risks caused by battery disposal or long-term idleness. Attached Figure Description

[0034] Figure 1 A schematic diagram of the structure of an energy storage device for the secondary utilization of old batteries provided in this embodiment of the present invention. Figure 1 .

[0035] Figure 2 A schematic diagram of the structure of an energy storage device for the secondary utilization of old batteries provided in this embodiment of the present invention. Figure 2 .

[0036] Figure 3 A schematic diagram of the structure of an energy storage device for the secondary utilization of old batteries provided in this embodiment of the present invention. Figure 3 .

[0037] Figure 4 This is a schematic diagram of the cell structure in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of the present invention.

[0038] Figure 5 A schematic diagram of the structure of a nickel sheet in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of this utility model. Figure 1 .

[0039] Figure 6 The image shows a right view of a nickel sheet in an energy storage device for the secondary utilization of old batteries, as provided in an embodiment of this utility model.

[0040] Figure 7 This is a top view of a nickel sheet in an energy storage device for the secondary utilization of old batteries, provided in an embodiment of the present invention.

[0041] Figure 8 This is a top view of a large battery cell in an energy storage device for the secondary utilization of old batteries, provided as an embodiment of the present invention.

[0042] Figure 9 This is a bottom view of a large battery cell in an energy storage device for the secondary utilization of old batteries, provided as an embodiment of the present invention.

[0043] Figure 10A schematic diagram of the cell assembly in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of this utility model. Figure 1 .

[0044] Figure 11 A schematic diagram of the cell assembly in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of this utility model. Figure 2 .

[0045] Figure 12 A schematic diagram of the cell box in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of this utility model. Figure 1 .

[0046] Figure 13 A schematic diagram of the cell box in an energy storage device for the secondary utilization of old batteries, provided by an embodiment of this utility model. Figure 2 .

[0047] The reference numerals in the accompanying drawings include: cell assembly 1, cell 2, nickel sheet 3, vertical nickel sheet 31, oblique nickel sheet 32, protection plate 4, upper protection plate 41, lower protection plate 42, substrate 5, BMS board 6, side frame 7, cell box 8, top plate 81, bottom plate 82, and side plate 83. Detailed Implementation

[0048] The following detailed description illustrates the specific implementation method:

[0049] The implementation examples are basically as follows Figure 1 , Figure 2 As shown: An energy storage device for the secondary utilization of old batteries, the energy storage device includes a cell box 8 and a cell assembly 1 within the cell box 8. (As shown...) Figure 3 As shown, the battery cell box 8 includes a side plate 83, a top plate 81, and a bottom plate 82. The side plate 83 has a "U"-shaped structure, comprising a left side plate and a right side plate connected by an inner side plate. The top plate 81 is mounted on the upper end of the side plate 83, and the bottom plate 82 is mounted on the lower end of the side plate 83, together forming a semi-enclosed battery cell box 8. The battery cell assembly 1 includes M*N battery cells 2, which are welded together with nickel sheets 3 to form a large battery cell. Protective plates 4 are welded to the upper and lower ends of the large battery cell. A substrate 5 is mounted below one of the protective plates 4, and a BMS board 6 is mounted between the lower protective plate 42 and the substrate 5. Then, a "U"-shaped side frame 7 is mounted on the outside of the large battery cell, forming a usable battery cell assembly 1. In this embodiment, the side frame 7 has a similar structure to the side plate 83, and the side frame 7 can be placed inside the side plate 83.

[0050] Specifically, batch aging tests were conducted on old batteries of the same specification (i.e., old cells, referred to as "cell 2") to obtain aging data for each cell 2. Based on the test results, cells 2 with obvious performance abnormalities were first removed, and cells 2 with satisfactory performance were retained. Then, the remaining cells 2 were matched according to the aging data. Cells 2 with a voltage difference ≤20mV and an internal resistance difference ≤0.1mΩ were grouped together to ensure the performance consistency of cells 2 within the group and to avoid imbalance problems caused by excessive performance differences of individual cells 2.

[0051] like Figure 4 As shown, several cells 2 within the same cell group 1 are arranged in an 18S2P staggered pattern (18S: indicating 18 cells connected in series, 2P: indicating that every two cells are connected in parallel to form a unit, and then these units are connected in series), where M and N are both integers greater than or equal to 2. This staggered arrangement makes the spacing between adjacent cells 2 more uniform, avoiding the localized overheating problem caused by close arrangement, and ensuring that heat is evenly distributed within the cell group 1, thus improving overall heat dissipation performance. By flexibly adjusting the values ​​of M and N, the number and arrangement of cells 2 can be adjusted according to actual needs to adapt to energy storage devices of different sizes and capacities. Specifically, in this embodiment, M is 4 and N is 9, forming a cell group 1 consisting of 36 cells 2.

[0052] like Figure 5 , Figure 6 As shown, the battery cells 2 are welded together to form a large battery cell using nickel sheets 3 (i.e., 36 battery cells 2 are welded together to form a large battery cell using nickel sheets 3). Specifically, as shown... Figure 7As shown, the nickel sheet 3 includes two vertical nickel sheets 31 and two oblique nickel sheets 32, with adjacent vertical nickel sheets 31 connected by oblique nickel sheets 32. The vertical nickel sheets 31 are used to connect the front and rear cells 2 in parallel to form smaller cells, increasing the capacity of the cells 2. The oblique nickel sheets 32 are used to connect adjacent smaller cells on the left and right sides in series to form cell pairs, increasing the voltage and energy requirements of a single large cell. The vertical nickel sheets 31 have a length of 120mm-122mm, a width of 19mm-21mm, and a thickness of 0.2mm-0.5mm; the oblique nickel sheets 32 have a length of 12mm-15mm, a width of 4mm-6mm, and a thickness of 0.2mm-0.5mm. Specifically, in this embodiment, the vertical nickel sheet 31 has a length of 120.5 mm, a width of 20 mm, and a thickness of 0.3 mm, with allowable tolerances of ±0.2 mm in the length direction and ±0.3 mm in the width direction; the oblique nickel sheet 32 ​​has a length of 13.9 mm, a width of 4 mm, and a thickness of 0.3 mm. The design of the length and width of the vertical and oblique nickel sheets 31 and 32 enhances the connection stability of the nickel sheets 3, making them less prone to loosening or falling off during long-term use, ensuring the stability and reliability of the electrical connection, and ensuring that the nickel sheets 3 have sufficient insulation spacing, reducing the risk of short circuits due to improper dimensions. The design of the thickness of the vertical and oblique nickel sheets 31 and 32 ensures that the nickel sheets 3 have sufficient tensile and bending resistance, enabling them to withstand greater mechanical stress during use, as well as higher current densities, avoiding melting problems caused by excessive current. Furthermore, the angle formed between the vertical nickel sheet 31 and the oblique nickel sheet 32 ​​is 40-50 degrees. Specifically, in this embodiment, the angle formed between the vertical nickel sheet 31 and the oblique nickel sheet 32 ​​is 45 degrees. The reasonable angle design allows the nickel sheet 3 to adapt to the staggered arrangement of the battery cell 2, making the connection of the nickel sheet 3 more stable and better able to resist external vibration and impact during use, thereby enhancing the mechanical strength of the entire battery cell assembly 1.

[0053] In this embodiment, a nickel sheet 3 has four rectangular holes, each measuring 7mm x 5mm, which can be used to weld four battery cells 2 to form a battery cell pair. When welding the nickel sheets 3 onto all the battery cells 2, the arrangement of the nickel sheets 3 at the upper and lower ends of the battery cells 2 is different; the upper and lower ends of the battery cells 2 are welded in an alternating manner. Figure 8 , Figure 9As shown, taking a nickel sheet 3 as a unit, nickel sheets 3 are welded to the upper end of the battery cell 2 in sequence from left to right, and nickel sheets 3 are welded to the lower end of the battery cell 2 in sequence from right to left, thus forming a staggered welding. The structural design of the nickel sheet 3 simplifies the welding process, reduces the unnecessary use of nickel sheets 3 when completing the series and parallel connection of the battery cells 2, and makes the welding path more concise, reducing the possibility of errors during the welding process. When the nickel sheets 3 are welded, 36 battery cells 2 form a large battery cell.

[0054] The protection board 4 is a high-voltage protection board, which can withstand high voltage and prevent the battery cells from being damaged due to overvoltage or causing safety accidents. The protection board 4 is a rectangular board, and the cross-sectional area of the protection board 4 is larger than the lateral area of the large battery cell, so that the protection board 4 can completely cover or even exceed the edge of the large battery cell, providing an additional protective layer, which can prevent external impacts and collisions from directly acting on the battery cells 2 and reduce the risk of damage to the battery cells 2. The protection board 4 includes an upper protection board 41 and a lower protection board 42, and the thicknesses of both the upper protection board 41 and the lower protection board 42 are 30 mm - 33 mm. Specifically, in this embodiment, the thicknesses of both the upper protection board 41 and the lower protection board 42 are 31.2 mm. The thickness design of the upper protection board 41 and the lower protection board 42 provides sufficient mechanical support for the battery cell group 1, which can prevent the battery cell group 1 from being deformed or damaged due to external impacts or pressures, thereby improving the stability of the battery cell group 1. After the battery cells 2 are welded into a large battery cell, as Figure 10 、 Figure 11 shown, the upper protection board 41 and the lower protection board 42 are welded to the upper and lower ends of the large battery cell respectively to prevent external impacts and collisions from directly acting on the battery cells 2, thereby reducing the risk of damage to the battery cells 2.

[0055] At the same time, a substrate 5 is installed below the lower protection board 42, and a BMS board 6 is installed between the lower protection board 42 and the substrate 5. The gap between the lower protection board 42 and the substrate 5 fits tightly with the BMS board 6, so that the BMS board 6 will not be displaced or loosened during use, avoiding electrical connection failures caused by vibrations or other external factors, saving space, reducing unnecessary redundant parts, and making the overall design more concise and efficient.

[0056] In addition, a "C-shaped" side frame 7 is installed outside the large battery cell. The side frame 7 includes a left long plate and a right long plate, and the left long plate and the right long plate are connected by an inner plate to form a semi-surrounding structure with three closed sides. The upper part of the side frame 7 is connected to the upper protection board 41, and the lower part of the side frame 7 is connected to the substrate 5, thus forming a stable battery cell group 1.

[0057] After the battery cell group 1 is formed, the battery cell group 1 needs to be placed in the battery cell box 8. The battery cell box 8 plays a protective role, provides physical protection for the internal battery cell group 1, enhances the overall rigidity and stability of the entire battery cell group 1, and can prevent external impacts, collisions or drops from damaging the battery cells 2. AsFigure 12 , Figure 13 As shown, the cell box 8 includes a side plate 83, a top plate 81, and a bottom plate 82. The side plate 83 has a "U"-shaped structure, comprising a left side plate and a right side plate, connected by an inner side plate to form a semi-enclosed structure with three closed sides. The top plate 81 is installed at the upper end of the side plate 83, and the bottom plate 82 is installed at the lower end of the side plate 83, together forming a semi-enclosed cell box 8. After the cell assembly 1 is formed, it is placed in the cell box 8 to form a complete energy storage device. The cell box 8 fits tightly with the cell assembly 1, ensuring that the cell assembly 1 remains stable within the cell box 8, reducing damage to the cell 2 caused by shaking or collisions during use. It also reduces unnecessary gaps between the cell assembly 1 and the cell box 8, lowering the risk of short circuits due to foreign objects entering the cell box 8.

[0058] The specific implementation process is as follows:

[0059] In this embodiment, a 400kWh commercial and industrial energy storage project is used as an example, and the battery cell model 2 used is Guoxuan 33140.

[0060] Step 1: Screening is carried out. In the same cell group 1, the voltage difference between cells 2 is ≤20mV and the internal resistance difference is ≤0.1mΩ.

[0061] Step 2: First, connect 36 3.2V 15AH cells 2 in parallel in pairs through vertical nickel plates 31 to form a small 3.2V 30AH cell;

[0062] Step 3: Then, connect 18 small 3.2V 30AH cells 2 in series to form a large 57.6V 30AH cell using the oblique nickel plate 32;

[0063] Step 4: Assemble the large battery cells by installing the protection board 4, side frame 7, base plate 5 and BMS board 6 respectively, thereby forming the battery cell group 1;

[0064] Step 5: Place the formed cell assembly 1 into the cell box 8 to form an energy storage device;

[0065] Step Six: Nine 57.6V 30AH energy storage devices are connected in parallel to form a 57.6V 270AH battery pack. Then, 13 battery packs are connected in parallel to form a battery cluster, which is then connected to a high-voltage control unit (BCU). Finally, two high-voltage control units are connected to a power supply system (PCS) in parallel. Based on power consumption, the photovoltaic panels and MPPT are arranged appropriately to form a 400kWh off-grid industrial and commercial energy storage system. This system enables photovoltaic power to supply both the energy storage and the load; when there is no photovoltaic power, the energy storage supplies power to the load.

[0066] This solution overcomes the technological prejudice that "old battery cells are unusable." Traditionally, old battery cells are considered unsuitable for reuse due to performance degradation and potential safety hazards, and are often discarded or left unused for extended periods. However, this solution, through proper selection and rearrangement of old battery cells, successfully achieves their reuse, constructing a new energy storage device and effectively reducing resource waste.

[0067] Specifically, this solution effectively matches and safely groups old battery cells in inventory based on valid aging data, ensuring the safety and feasibility of secondary utilization. During grouping, the voltage difference between cells 2 within the same group is controlled to be ≤20mV, and the internal resistance difference to be ≤0.1mΩ, ensuring a balance between recycling efficiency and performance consistency, and guaranteeing the overall performance and safety of the combined cells. Furthermore, in terms of structural design, several cells 2 within the same cell group 1 are arranged in a staggered "18S2P" configuration, connected in parallel via vertical nickel plates 31 and in series via diagonal nickel plates 32. This design not only ensures overall charge capacity but also avoids localized overheating caused by close arrangement, allowing heat to be evenly distributed within the cell group 1 and improving overall heat dissipation performance.

[0068] In summary, this solution achieves the effective reuse of old battery cells through the construction of energy storage devices. This not only avoids resource waste and maximizes resource utilization, but also avoids inventory accumulation to a certain extent, effectively mitigating the cost risks caused by battery disposal or long-term idleness.

[0069] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of this utility model. These modifications and improvements should also be considered within the scope of protection of this utility model, and will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An energy storage device for the secondary utilization of old batteries, characterized in that: It includes a battery cell box and a battery cell group inside the battery cell box; the battery cell group includes M*N battery cells, the battery cells are connected by nickel sheets to form a large battery cell, the nickel sheets include vertical nickel sheets for parallel connection and diagonal nickel sheets for series connection, and the vertical nickel sheets are connected by diagonal nickel sheets; upper and lower protection plates are respectively provided at the upper and lower ends of the large battery cell, a substrate is provided below the lower protection plate, and a BMS board is provided between the lower protection plate and the substrate; a side frame is provided outside the large battery cell, the side frame is in a "U" shape, the upper part of the side frame is connected to the upper protection plate, and the lower part of the side frame is connected to the substrate.

2. The energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The battery cells are arranged in a staggered manner, and both M and N are integers greater than or equal to 2.

3. The energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The voltage difference between the battery cells ≤ 20mv, and the internal resistance difference ≤ 0.1mΩ.

4. The energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The angle between the vertical nickel sheet and the diagonal nickel sheet is 40 - 50 degrees.

5. An energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The length of the vertical nickel sheet is 120mm - 122mm, the width of the vertical nickel sheet is 19mm - 21mm, and the thickness of the vertical nickel sheet is 0.2mm - 0.5mm; the length of the diagonal nickel sheet is 12mm - 15mm, the width of the diagonal nickel sheet is 4mm - 6mm, and the thickness of the diagonal nickel sheet is 0.2mm - 0.5mm.

6. The energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: Both the upper protection plate and the lower protection plate are high-voltage protection plates, and the thickness of both the upper protection plate and the lower protection plate is 30mm - 33mm.

7. An energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The battery cell box includes side plates, the side plates are in a "U" shaped structure, a top plate is provided at the upper end of the side plates, and a bottom plate is provided at the lower end of the side plates.

8. An energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The battery cell box is closely fitted with the battery cell group.

9. An energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: Nickel sheets are welded at the upper and lower ends of the battery cells in a staggered manner.

10. An energy storage device for the secondary utilization of old batteries according to claim 1, characterized in that: The cross-sectional area of the upper protection plate is larger than the lateral area of the large battery cell.

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