Method for assembling battery boxes without partitions

Abstract

The present invention relates to the technical field of battery processing, and specifically discloses a method for packing a battery pack without a partition. The method comprises the following steps: making a lithium-ion battery cell, placing the lithium-ion battery cell after liquid injection at a resting temperature for a resting time; after the resting time, using a formation circuit to negatively pressure form the lithium-ion battery cell until the voltage of the lithium-ion battery cell reaches a first voltage; closing the liquid injection port of the lithium-ion battery cell; loading a plurality of lithium-ion batteries into a receiving slot of a battery box until the receiving slot is filled, and then connecting all lithium-ion batteries in series to form a battery pack; charging the battery pack until the voltage of the battery pack reaches a second voltage; encapsulating the battery pack to complete the packing of the battery box. The method utilizes the thickness increased by the gas production of the battery pack to achieve the fixation of the battery pack, so as to improve the energy density of the battery pack, so that the electrode piece after the gas production of the battery is not easily squeezed to affect the electrical performance of the lithium-ion battery cell, thereby realizing the large-scale production of battery packs.

Description

Technical Field

[0001] The invention relates to the technical field of storage battery processing, in particular to a method for assembling a battery box without a partition. Background Art

[0002] As the automotive battery market and the energy storage battery market increase the requirements for the energy density of lithium battery packs, the demand for battery pack improvements is also increasing. At present, in addition to increasing the energy density of the battery cell itself, more and more improvements are aimed at reducing non-essential components in the battery pack. Under the premise that the energy of the battery cell remains unchanged, the purpose of increasing the energy density of the battery pack is achieved by reducing the mass of the battery pack. The reduction of components in the battery pack can reduce the overall mass of the battery pack, thereby increasing the mass energy density and the vehicle's range.

[0003] In the prior art, the volume utilization of the battery pack can be improved by eliminating or reducing the end plates, side plates and fasteners such as screws used to fix the modules. The above improvements will make the battery assembly process simpler, thereby reducing the manufacturing costs such as manpower and material resources. In addition, the cost of parts is reduced, and the cost of the battery pack will also be reduced.

[0004] At present, the structural improvement of simplified modules still cannot remove the cable ties used to fix the modules. The presence of cable ties will cause uneven force on the battery pack. At the same time, cable ties generally adopt steel structures, which also occupy a certain volume and mass, limiting the further improvement of volume and mass energy density. In the original scheme of high group margin without partitions, the battery cells will expand only after charging. Due to space limitations when entering the box for discharge, and the limited expansion of each battery cell, relying solely on charging expansion may cause the battery cells to still not be tightly arranged inside, resulting in the problem of loose or displaced battery cells. At the same time, the battery cells will cause the pole pieces to expand due to charging, making the thickness of the battery thicker, causing the internal pressure between the electrodes to change, and the thickening of the battery cells will form an extrusion force on the inside. The long-term extrusion of the pole pieces will affect the battery's cycle effect and electrical performance. Summary of the invention

[0005] The purpose of the present invention is to provide a battery pack assembly method without a partition, which utilizes the thickness increased by the battery pack due to gas production to fix the battery pack, so as to improve the energy density of the battery pack and make the electrode sheet after the battery gas production less likely to be squeezed and affect the electrical performance of the lithium-ion battery cell, thereby realizing large-scale production of battery packs.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A method for assembling a battery box without a partition comprises the following steps:

[0008] S1: preparing a lithium-ion battery cell, placing the lithium-ion battery cell after liquid injection at a resting temperature for a resting time;

[0009] S2: after the rest time, negatively pressure forming the lithium ion battery cell using a forming circuit until the voltage of the lithium ion battery cell reaches a first voltage;

[0010] S3: closing the injection port of the lithium-ion battery cell;

[0011] S4: loading the plurality of lithium-ion cells into the receiving slots of the battery box until the receiving slots are filled, and then connecting all the lithium-ion cells in series to form a battery pack;

[0012] S5: charging the battery pack until the voltage of the battery pack reaches a second voltage;

[0013] S6: Packaging the battery pack to complete the packing of the battery box.

[0014] As a preferred technical solution for the method of assembling a battery box without a partition, the step S3 includes the following detailed steps: sealing, coating and attaching an insulating sheet to the liquid injection port of the lithium-ion battery cell.

[0015] As a preferred technical solution for the method of assembling a battery box without a separator, the charge of the formation circuit is 0-1.0 coulomb.

[0016] As a preferred technical solution for the method of assembling a battery box without a partition, the lithium-ion battery cell is a nickel-cobalt-lithium battery cell or a lithium phosphate battery cell.

[0017] As a preferred technical solution for the partition-free battery assembly box method, if the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the first voltage is 1.5-3.0 volts, and if the lithium-ion battery cell is a lithium phosphate battery cell, the first voltage is 1.0-3.2 volts.

[0018] As a preferred technical solution for the partition-free battery assembly box method, if the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the second voltage is 3.0N-3.5N volts; if the lithium-ion battery cell is a lithium phosphate battery cell, the second voltage is 3.2N-3.5N volts; wherein N is the number of the lithium-ion battery cells.

[0019] As a preferred technical solution for the method of assembling a battery box without a partition, the nickel-cobalt-lithium battery cell is a nickel-cobalt-manganese-oxide lithium battery cell.

[0020] As a preferred technical solution of the partition-free battery pack assembly method, the lithium phosphate battery cell is a lithium iron phosphate battery cell or a lithium iron manganese phosphate battery cell.

[0021] As a preferred technical solution for the method of assembling a battery box without a partition, the shape of the receiving groove is a rectangular parallelepiped.

[0022] As a preferred technical solution of the method for assembling a battery box without a partition, the lithium-ion battery cell is in the shape of a cuboid.

[0023] Beneficial effects of the present invention:

[0024] This partition-free battery packing method completes the packing operation of the battery pack by charging twice in succession. The thickness increased by the gas production of the battery pack is used to fix the battery pack, thereby improving the energy density of the battery pack and making it difficult for the pole pieces after the battery gas production to be squeezed and affect the electrical performance of the lithium-ion battery cell, thereby realizing the large-scale production of battery packs. The above improvements eliminate the need for components to fix the lithium-ion battery cells, reduce the risk of uneven force on the battery pack, reduce the overall mass of the battery pack, increase the mass energy density, and increase the cruising range of the vehicle. The above process is simple and reliable, reduces the workload of operators, improves the packing efficiency of the battery pack, and ensures the stable installation of the lithium-ion battery cells in the battery box. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of a method for assembling a battery box without a partition provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0027] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0029] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0030] like Figure 1 As shown, this embodiment provides a method for assembling a battery box without a partition, comprising the following steps:

[0031] Step 1: Make a lithium-ion battery cell, and place the lithium-ion battery cell with liquid injection at a resting temperature for a resting time.

[0032] Step 2: After the static time, negative-pressure formation is performed on the lithium-ion battery cell by using a formation circuit until the voltage of the lithium-ion battery cell reaches a first voltage.

[0033] Step 3: Seal the filling port of the lithium-ion battery cell.

[0034] Step 4: Install multiple lithium-ion cells into the receiving slots of the battery box until the receiving slots are filled, and then connect all the lithium-ion cells in series to form a battery pack.

[0035] Step 5: Charge the battery pack until the voltage of the battery pack reaches a second voltage.

[0036] Step 6: Encapsulate the battery pack and complete the packing of the battery box.

[0037] This partition-free battery packing method completes the packing operation of the battery pack by charging twice in succession. The thickness increased by the gas production of the battery pack is used to fix the battery pack, thereby improving the energy density of the battery pack and making it difficult for the pole pieces after the battery gas production to be squeezed and affect the electrical performance of the lithium-ion battery cell, thereby realizing the large-scale production of battery packs. The above improvements eliminate the need for components to fix the lithium-ion battery cells, reduce the risk of uneven force on the battery pack, reduce the overall mass of the battery pack, increase the mass energy density, and increase the cruising range of the vehicle. The above process is simple and reliable, reduces the workload of operators, improves the packing efficiency of the battery pack, and ensures the stable installation of the lithium-ion battery cells in the battery box.

[0038] In this embodiment, the standing temperature is 30-60 degrees Celsius, and the standing time is 12-72 hours. The above limits can ensure the wetting effect of the electrolyte on the electrode.

[0039] Step one prepares for the subsequent formation process; step five is the operation of charging the battery pack, which can cause the lithium-ion battery cell to continue to produce gas, thereby increasing the thickness of the lithium-ion battery cell, and then making the battery pack and the receiving slot have an interference fit, thereby achieving the positioning effect of the battery pack in the battery box.

[0040] The method of assembling a battery box without a partition is based on the existing manufacturing technology of lithium-ion cells and battery packs. It does not require any new equipment or new fixtures, and will not increase production costs. There is no need to set partitions, fixing frames or tie ties between the lithium-ion cells in the battery pack for fixing, thereby further improving the space utilization of the battery pack, reducing the number of parts and simplifying the assembly steps of the battery pack. The lithium-ion cells are assembled into the battery box when the SOC (state of charge) is below 0%. Since the battery pack cannot be lower than 0% SOC during use, the thickness of the lithium-ion cells cannot be less than 0% SOC, so the lithium-ion cells will not become thinner as the SOC decreases, thereby avoiding the situation where the battery pack is loose and detached. Since a part of the formation is carried out after packaging, the expanded part of the lithium-ion cell is gas. When squeezed, the gas in the lithium-ion cell is mainly squeezed, thereby reducing the squeezing force on the electrode sheet and avoiding the influence on the electrical performance and cycle performance of the battery.

[0041] Preferably, the shape of the receiving tank is a cuboid; the shape of the lithium-ion battery cell is a cuboid.

[0042] The above structural design is simple and reliable, which ensures the stable installation of the battery pack in the receiving slot, reduces the space occupied by the battery box, reduces the difficulty of loading the lithium-ion battery cell into the receiving slot, simplifies the packing process, and improves work efficiency.

[0043] Specifically, the outer surface of the battery pack is closely attached to the wall of the receiving groove. The above design makes it unnecessary to use spacers or fixing frames to complete the positioning of the battery pack in the receiving groove and the process of forming the battery pack with each lithium-ion battery cell.

[0044] In this embodiment, step three includes the following detailed steps: sealing, coating and attaching an insulating sheet to the injection port of the lithium-ion battery cell. By sequentially performing the above steps, the operation of sealing the injection port of the lithium-ion battery cell can be successfully completed, ensuring the yield rate of the battery pack assembly method without a partition.

[0045] Preferably, the charge of the formation circuit is 0-1.0 coulomb.

[0046] In this embodiment, the lithium-ion battery cell is a nickel-cobalt-lithium battery cell or a lithium phosphate battery cell.

[0047] Preferably, if the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the first voltage is 1.5-3.0 volts, and if the lithium-ion battery cell is a lithium phosphate battery cell, the first voltage is 1.0-3.2 volts. If the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the second voltage is 3.0N-3.5N volts, and if the lithium-ion battery cell is a lithium phosphate battery cell, the second voltage is 3.2N-3.5N volts; wherein N is the number of lithium-ion batteries.

[0048] In other implementations of this embodiment, the charge amount, the first voltage and the second voltage of the formation circuit are determined by the operator. The specific values ​​are selected by conventional technical means in the field and are mastered by technicians in the field, so they will not be elaborated here.

[0049] In this embodiment, the nickel-cobalt-lithium battery cell is a nickel-cobalt-manganese-oxide lithium battery cell; the lithium phosphate battery cell is a lithium iron phosphate battery cell or a lithium iron manganese phosphate battery cell. Lithium nickel-cobalt-manganese-oxide has excellent electrochemical properties such as high capacity, good thermal stability, and wide charge and discharge voltage. Lithium iron phosphate has the advantages of high energy density, low price, environmental friendliness, long service life, high safety performance, high structural stability, and good cycle performance. Lithium iron manganese phosphate has the advantages of high battery energy density, strong endurance, and low manufacturing cost.

[0050] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A method for assembling a battery box without a partition, characterized in that: The following steps are involved: S1: preparing a lithium-ion battery cell, placing the lithium-ion battery cell after liquid injection at a resting temperature for a resting time; S2: after the rest time, negatively pressure forming the lithium ion battery cell using a forming circuit until the voltage of the lithium ion battery cell reaches a first voltage; S3: closing the injection port of the lithium-ion battery cell; S4: loading the plurality of lithium-ion cells into the receiving slots of the battery box until the receiving slots are filled, and then connecting all the lithium-ion cells in series to form a battery pack; S5: charging the battery pack until the voltage of the battery pack reaches a second voltage; S6: Packaging the battery pack to complete packing of the battery box; The operation of charging the battery pack in step S5 can cause the lithium-ion battery cell to continue to generate gas, thereby increasing the thickness of the lithium-ion battery cell, thereby causing the battery pack to have an interference fit with the receiving slot; After packing, a part of the formation is carried out, and the expanded part of the lithium ion battery cell is gas. When squeezing, the gas in the lithium ion battery cell is mainly squeezed.

2. The method for assembling a battery box without a partition according to claim 1, characterized in that: The step S3 includes the following detailed steps: sealing, coating and attaching an insulating sheet to the liquid injection port of the lithium-ion battery cell.

3. The method for assembling a battery box without a partition according to claim 1, characterized in that: The charge amount of the formation circuit is 0-1.0 coulomb.

4. The method for assembling a battery box without a partition according to claim 1, characterized in that: The lithium-ion battery cell is a nickel-cobalt-lithium battery cell or a lithium phosphate battery cell.

5. The method for assembling a battery box without a partition according to claim 4, characterized in that: If the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the first voltage is 1.5-3.0 volts. If the lithium-ion battery cell is a lithium phosphate battery cell, the first voltage is 1.0-3.2 volts.

6. The method for assembling a battery box without a separator according to claim 4, characterized in that: If the lithium-ion battery cell is a nickel-cobalt lithium battery cell, the second voltage is 3.0N-3.5N volts; if the lithium-ion battery cell is a lithium phosphate battery cell, the second voltage is 3.2N-3.5N volts; wherein N is the number of the lithium-ion battery cells.

7. The method for assembling a battery box without a partition according to claim 4, characterized in that: The nickel-cobalt-lithium battery cell is a nickel-cobalt-manganese-oxide lithium battery cell.

8. The method for assembling a battery box without a separator according to claim 4, characterized in that: The lithium phosphate battery cell is a lithium iron phosphate battery cell or a lithium iron manganese phosphate battery cell.

9. The method for assembling a battery box without a separator according to any one of claims 1 to 8, characterized in that: The shape of the containing groove is a cuboid.

10. The method for assembling a battery box without a partition according to claim 9, characterized in that: The lithium-ion battery cell is in the shape of a cuboid.

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