Liquid storage device, lithium battery including the same, and manufacturing method thereof

Abstract

The present invention discloses a liquid storage device and a lithium battery including the liquid storage device and a manufacturing method thereof. The liquid storage device includes at least a first liquid storage member and a second liquid storage member, the structures of the first liquid storage member and the second liquid storage member are completely the same, and the first liquid storage member is installed above the second liquid storage member; the first liquid storage member and the second liquid storage member both store electrolyte; the first liquid storage member includes a first liquid storage member body, a first liquid storage hole for electrolyte circulation or storage, and a first needle winding hole for accommodating a first winding needle; the first needle winding is used to drive the first liquid storage member to rotate; the second liquid storage member includes a second liquid storage member body, a second liquid storage hole for electrolyte circulation or storage, and a second needle winding hole for accommodating a second winding needle; the second needle winding is used to drive the second liquid storage member to rotate; the present invention can continuously replenish the electrolyte consumed during the battery cycle, thereby improving the battery cycle life.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a liquid storage device, a lithium battery comprising the liquid storage device, and a manufacturing method thereof. Background Art

[0002] The wound lithium battery is made by winding the positive electrode sheet, negative electrode sheet and isolation film with a winding needle. After the winding is completed, the winding needle is pulled out from the inside of the winding core, and then the winding core is hot-pressed or cold-pressed to shape. However, in the process of pulling the winding needle out of the winding core, the isolation film is easily brought out of the battery body along with the winding needle, which poses the risk of diaphragm wrinkling, electrode sheet misalignment, and even direct contact and short circuit between the positive and negative electrodes. In addition, there is almost no transition arc zone at the corner of the inner circle electrode after hot pressing or cold pressing, which is equivalent to directly folding the electrode in half, which is very easy to cause problems such as electrode sheet powder loss and breakage, posing a safety hazard. For this problem, the current main approach is to improve the flexibility of the electrode to a certain extent to improve the powder loss phenomenon, but the effect is very limited.

[0003] Lithium batteries include positive electrode sheets, negative electrode sheets, separators and electrolytes. Among them, the electrolyte is the carrier for lithium ions to be embedded and de-embedded between the positive and negative electrodes. It will be continuously consumed during the battery cycle. The amount of electrolyte retained plays a key role in the performance of the battery.

[0004] For example, Chinese patent CN107579174A discloses a soft-pack polymer power battery with ultra-long cycle life and high energy density. The specific implementation method is: by adding a lug protection spacer with a liquid storage function inside the battery, the amount of electrolyte inside the battery can be increased, and the consumed electrolyte can be continuously replenished during the cycle process to ensure the ultra-long cycle life of the battery. Although the above method can increase the amount of electrolyte and thus improve the battery cycle performance, it is inconvenient to install a lug protection spacer between the two lugs, and there are few application scenarios. It is only applicable to the case where the top packaging area of ​​the soft-pack battery is wide.

[0005] In view of this, it is indeed necessary to provide a technical solution to the above problems. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned defects in the prior art and to provide a liquid storage device and a lithium battery including the liquid storage device and a method for manufacturing the same; the curvature at the corner of the inner circle pole piece can be reduced, and the powder shedding and breakage of the pole piece can be improved; the risks of diaphragm wrinkling, pole piece dislocation and short circuit can be avoided; the electrolyte consumed during the battery cycle can be continuously replenished, thereby improving the battery cycle life.

[0007] To achieve the above-mentioned purpose, the present invention provides a liquid storage device, including at least a first liquid storage member and a second liquid storage member, the structures of the first liquid storage member and the second liquid storage member are exactly the same, and the first liquid storage member is installed above the second liquid storage member; the first liquid storage member and the second liquid storage member both store electrolyte; the first liquid storage member includes a first liquid storage member body, a first liquid storage hole for the circulation or storage of electrolyte, and a first needle winding hole for accommodating a first winding needle; the first winding needle is used to drive the first liquid storage member to rotate; the second liquid storage member includes a second liquid storage member body, a second liquid storage hole for the circulation or storage of electrolyte, and a second needle winding hole for accommodating a second winding needle; the second winding needle is used to drive the second liquid storage member to rotate.

[0008] Preferably, the first liquid storage hole is a through hole for electrolyte circulation or a blind hole for electrolyte storage; the number of the first liquid storage holes is at least one; the diameter of the first liquid storage hole is between 0.5 and 3 mm; the second liquid storage hole is a through hole for electrolyte circulation or a blind hole for electrolyte storage; the number of the second liquid storage holes is at least one; the diameter of the second liquid storage hole is between 0.5 and 3 mm.

[0009] Preferably, the number of the first and second needle holes is at least one; and the diameters of the first and second needle holes are between 1 and 5 mm.

[0010] Preferably, the first liquid storage member and the second liquid storage member are polymer material components made of polyethylene, polypropylene, polyethylene terephthalate or polycarbonate polymers that are resistant to corrosion by electrolyte.

[0011] Preferably, the first liquid storage member and the second liquid storage member are in a semi-cylindrical shape or a semi-elliptical cylindrical shape.

[0012] Preferably, the first winding needle comprises a first winding needle body and a first winding needle insertion portion installed at one end of the first winding needle body, and a first winding needle piston portion is also installed on the first winding needle insertion portion; the first winding needle insertion portion is inserted into the first winding needle hole; the first winding needle piston portion is in close contact with the first winding needle hole, thereby driving the first liquid storage member to rotate;

[0013] The second winding needle includes a second winding needle body and a second winding needle insertion portion installed at one end of the second winding needle body, and a second winding needle piston portion is also installed on the second winding needle insertion portion; the second winding needle insertion portion is inserted into the second winding needle hole; the second winding needle piston portion is in close contact with the second winding needle hole, thereby driving the second liquid storage part to rotate.

[0014] The present invention also provides a lithium battery including a liquid storage device as described above, characterized in that it includes a winding core, the winding core includes a positive electrode sheet, a negative electrode sheet and a diaphragm, and is wound by the positive electrode sheet, the negative electrode sheet and the diaphragm, the first liquid storage component and the second liquid storage component clamp one end of the positive electrode sheet, the negative electrode sheet and the diaphragm in the middle, and the liquid storage device is installed inside the winding core.

[0015] Preferably, the winding core is encapsulated by a steel shell, an aluminum shell or an aluminum-plastic film to produce a steel shell, an aluminum shell or an aluminum-plastic film lithium battery.

[0016] The present invention also provides a method for manufacturing the lithium battery comprising the liquid storage device as described above, comprising the following steps:

[0017] Step S1: preparing a positive electrode sheet, a negative electrode sheet and a separator;

[0018] Step S2: inserting the first winding needle into the first winding needle hole in the first liquid storage member; and fixing the first liquid storage member by the first winding needle piston; inserting the second winding needle into the second winding needle hole in the second liquid storage member; and fixing the second liquid storage member by the second winding needle piston;

[0019] Step S3: clamping the positive electrode sheet, the negative electrode sheet and one end of the separator between the first liquid storage member and the second liquid storage member;

[0020] Step S4: driving the first winding needle and the second winding needle to rotate, thereby winding the positive electrode sheet, the negative electrode sheet and the separator into a winding core;

[0021] Step S5: pulling out the first winding needle and the second winding needle from the first liquid storage member and the second liquid storage member respectively, and retaining the first liquid storage member and the second liquid storage member inside the winding core;

[0022] Step S6: Encapsulate the coil core with a steel shell, an aluminum shell or an aluminum-plastic film to produce a steel shell, an aluminum shell or an aluminum-plastic film lithium battery.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The liquid storage device of the present invention has the function of storing electrolyte. Specifically, electrolyte is stored in both the first liquid storage member and the second liquid storage member; the first liquid storage member includes a first liquid storage hole for the circulation or storage of electrolyte; the second liquid storage member includes a second liquid storage hole for the circulation or storage of electrolyte. During the battery cycle, the electrolyte is mainly consumed in the destruction and reforming process of the SEI film at the negative electrode interface. When the electrolyte is consumed to the point where the battery is in a lean state, the cycle life will be rapidly attenuated. The liquid storage device can provide additional electrolyte, thereby delaying the time for the battery system to enter a lean state, thereby increasing the battery cycle life.

[0025] 2. The first liquid storage member and the second liquid storage member of the present invention can be fixed on the first winding needle and the second winding needle respectively. Since the surfaces of the first liquid storage member and the second liquid storage member have a certain curvature, there will be no problems of powder falling and broken pieces during the winding process; and after the winding of the core is completed, the liquid storage device remains inside the core. When the core is hot-pressed or cold-pressed, the curvature of the corner of the pole piece on the inner circle of the core can be reduced, thereby improving the problems of powder falling and broken pieces of the pole piece.

[0026] 3. In the present invention, the first liquid storage member and the second liquid storage member are wound synchronously with the first winding needle and the second winding needle. After the winding of the winding core is completed, it is only necessary to pull out the winding needle from the winding needle hole of the liquid storage device. This can fundamentally avoid the risk of diaphragm wrinkling, electrode misalignment and even direct contact short circuit between the positive and negative electrodes caused by poor needle pulling of the winding core. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 is a schematic diagram of a liquid storage device provided by the present invention;

[0029] Figure 2 It is a comparison chart of the cycle curves of the lithium battery of the embodiment provided by the present invention and the lithium battery of the comparative example.

[0030] Included in the figure are:

[0031] 1-first liquid storage component, 2-second liquid storage component, 101-first liquid storage component body, 102-first liquid storage hole, 103-first needle winding hole, 3-first needle winding, 201-second liquid storage component body, 202-second liquid storage hole, 203-second needle winding hole, 4-second needle winding, 303-first needle winding body, 301-first needle winding insertion part, 302-first needle winding piston part, 403-second needle winding body, 401-second needle winding insertion part, 402-second needle winding piston part. DETAILED DESCRIPTION

[0032] The technical scheme in this embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in this embodiment of the present invention. Obviously, the described embodiment is one embodiment of the present invention, not all embodiments of the present invention. Based on this embodiment of the present invention, all other embodiments of the present invention obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] Embodiment 1

[0034] Please refer to Figure 1 , Embodiment 1 of the present invention provides a liquid storage device.

[0035] like Figure 1 As shown, the liquid storage device at least includes a first liquid storage component 1 and a second liquid storage component 2, and the first liquid storage component 1 and the second liquid storage component 2 are used in pairs and matched with each other, and there can be two or four of them; in the first embodiment, the liquid storage device includes a first liquid storage component 1 and a second liquid storage component 2, and the structures of the first liquid storage component 1 and the second liquid storage component 2 are exactly the same, and the first liquid storage component 1 is installed above the second liquid storage component 2; the first liquid storage component 1 and the second liquid storage component 2 are hollow structures inside, have a certain storage space, and store electrolyte.

[0036] As mentioned above, the liquid storage device has the function of storing electrolyte. Specifically, electrolyte is stored in both the first liquid storage component 1 and the second liquid storage component 2. Furthermore, the first liquid storage component 1 includes a first liquid storage hole 102 for electrolyte circulation or storage; the second liquid storage component 2 includes a second liquid storage hole 202 for electrolyte circulation or storage. During the battery cycle, the electrolyte is mainly consumed in the destruction and reforming process of the SEI film at the negative electrode interface. When the electrolyte is consumed to the point where the battery is in a lean state, the cycle life will be rapidly attenuated. The liquid storage device can provide additional electrolyte, thereby delaying the time for the battery system to enter a lean state, thereby increasing the battery cycle life.

[0037] like Figure 1 As shown, the first liquid storage component 1 includes a first liquid storage component body 101; a plurality of first liquid storage holes 102 are provided on the first liquid storage component body 101; the first liquid storage hole 102 is used for the circulation or storage of electrolyte; specifically, the first liquid storage hole 102 can be a through hole for the circulation of electrolyte, or a blind hole for the storage of electrolyte; it can also be a mixture of through holes and blind holes, that is, there are both through holes and blind holes; and the number of the first liquid storage hole 102 is at least one; the diameter of the first liquid storage hole 102 is between 0.5 and 3 mm; at least one first winding needle hole 103 is also provided on the side of the first liquid storage component body 101; the first winding needle hole 103 is used to accommodate the first winding needle 3; the diameter of the first winding needle hole 103 is between 1 and 5 mm; the first winding needle 3 is inserted into the first winding needle hole 103 to drive the first liquid storage component 1 to rotate, thereby performing the winding work of the winding core.

[0038] like Figure 1As shown, the second liquid storage member 2 is located below the first liquid storage member 1, and the second liquid storage member 2 includes a second liquid storage member body 201; a plurality of second liquid storage holes 202 are provided on the second liquid storage member body 201; the second liquid storage hole 202 is also used for the circulation or storage of electrolyte; specifically, the second liquid storage hole 202 can be a through hole for the circulation of electrolyte, or a blind hole for the storage of electrolyte; it can also be a mixture of through holes and blind holes, that is, there are both through holes and blind holes; and the number of the second liquid storage hole 202 is at least one; the diameter of the second liquid storage hole 202 is between 0.5 and 3 mm; at least one second winding needle hole 203 is also provided on the side of the second liquid storage member body 201; the second winding needle hole 203 is used to accommodate the second winding needle 4; the diameter of the second winding needle hole 203 is between 1 and 5 mm; the second winding needle 4 is inserted into the second winding needle hole 203 to drive the second liquid storage member 2 to rotate, thereby performing the winding of the winding core.

[0039] The first liquid storage component 1 and the second liquid storage component 2 are polymer high molecular material components such as polyethylene PE, polypropylene PP, polyethylene terephthalate PET or polycarbonate PC that are resistant to electrolyte corrosion, have certain strength, and can prevent electrolyte corrosion.

[0040] like Figure 1 As shown, in this embodiment, the first liquid storage component 1 and the second liquid storage component 2 are both semi-cylindrical in shape, and the first liquid storage component 1 and the second liquid storage component 2 are combined together to form a complete cylinder; and the positive electrode plate, the negative electrode plate and the diaphragm are clamped between the first liquid storage component 1 and the second liquid storage component 2; further, the surfaces of the first liquid storage component 1 and the second liquid storage component 2 have an arc-shaped structure, which can reduce the curvature at the corners; further, the first liquid storage component 1 and the second liquid storage component 2 can also be semi-elliptical cylindrical or semi-U-shaped cylindrical.

[0041] The first liquid storage member 1 and the second liquid storage member 2 are respectively installed on the first winding needle 3 and the second winding needle 4. Since the surfaces of the first liquid storage member and the second liquid storage member have a certain curvature, and after the winding of the core is completed, the first liquid storage member 1 and the second liquid storage member 2 are reserved inside the core. When the core is hot-pressed or cold-pressed, the curvature of the corner of the pole piece of the inner circle of the core can be reduced, thereby improving the problem of powder loss and breakage of the pole piece.

[0042] like Figure 1 As shown, the first winding needle 3 comprises a first winding needle body 303 and a first winding needle insertion portion 301 mounted at one end of the first winding needle body 303 , and a first winding needle piston portion 302 is also mounted on the first winding needle insertion portion 301 .

[0043] The working method of the first winding needle 3 is as follows: first, since the diameter of the first winding needle insertion portion 301 is smaller than the diameter of the first winding needle hole 103, the first winding needle insertion portion 301 can be inserted into the first winding needle hole 103; secondly, the first winding needle piston portion 302 extends outward due to the internal pressure and is in close contact with the first winding needle hole 103; finally, the first winding needle 3 is driven to rotate, thereby driving the first liquid storage component 1 to rotate.

[0044] Furthermore, the interior of the first winding needle 3 may be a hollow structure, and when the first winding needle piston portion 302 is subjected to internal pressure, the piston extends outward, so that the diameter of the first winding needle piston portion 302 becomes larger, so that it can be in close contact with the first winding needle hole 103, so that the first liquid storage component 1 is fixed on the first winding needle 3, thereby driving the first liquid storage component 1 to rotate; when the first winding needle piston portion 302 is depressurized, the piston retracts inward, so that the diameter of the first winding needle piston portion 302 becomes smaller, so that it can be well separated from the first winding needle hole 103, so that the first winding needle 3 can be easily taken out from the first liquid storage component 1.

[0045] Similarly, the second winding needle 4 has the same function and structure as the first winding needle 3; specifically, Figure 1 As shown, the second winding needle 4 comprises a second winding needle body 403 at the end; a second winding needle insertion portion 401 is mounted at one end of the second winding needle body 403 , and a second winding needle piston portion 402 is also mounted on the second winding needle insertion portion 401 .

[0046] The working method of the second winding needle 4 is as follows: first, since the diameter of the second winding needle insertion portion 401 is smaller than the diameter of the second winding needle hole 203, the second winding needle insertion portion 401 can be inserted into the second winding needle hole 203; secondly, the second winding needle piston portion 402 extends outward due to the internal pressure and is in close contact with the second winding needle hole 203; finally, the second winding needle 4 is driven to rotate, thereby driving the second liquid storage component 2 to rotate.

[0047] Furthermore, the interior of the second winding needle 4 may be a hollow structure. When the second winding needle piston portion 402 is subjected to internal pressure, the piston extends outward, so that the diameter of the second winding needle piston portion 402 becomes larger, so that it can be in close contact with the second winding needle hole 203, so that the second liquid storage component 2 is fixed on the second winding needle 4, thereby driving the second liquid storage component 2 to rotate; when the second winding needle piston portion 402 is depressurized, the piston retracts inward, so that the diameter of the second winding needle piston portion 402 becomes smaller, so that it can be well separated from the second winding needle hole 203, so that the second winding needle 4 can be easily taken out from the second liquid storage component 2.

[0048] like Figure 1As shown, the first winding needle 3 drives the first liquid storage member 1 to perform rotational motion; the second winding needle 4 drives the second liquid storage member 2 to perform rotational motion; and the first winding needle 3 and the second winding needle 4 are wound synchronously, so that the first liquid storage member 1 and the second liquid storage member 2 are also wound synchronously. After the winding core is wound and formed, the first winding needle 3 and the second winding needle 4 are pulled out from the first winding needle hole 103 and the second winding needle hole 203 respectively; the risk of diaphragm wrinkling, pole piece misalignment and even direct contact short circuit between the positive and negative electrodes caused by poor winding core needle extraction can be fundamentally avoided.

[0049] Embodiment 2

[0050] Please refer to Figure 1 Embodiment 2 of the present invention provides a lithium battery including a liquid storage device as described in Embodiment 1.

[0051] The lithium battery includes a winding core and a liquid storage device installed inside the winding core; specifically, the winding core includes a positive electrode sheet, a negative electrode sheet and a separator, and is wound by the positive electrode sheet, the negative electrode sheet and the separator. Furthermore, the first liquid storage component 1 and the second liquid storage component 2 clamp one end of the positive electrode sheet, the negative electrode sheet and the separator in the middle, and then wind them.

[0052] Furthermore, the roll core may be packaged by a steel shell, an aluminum shell or an aluminum-plastic film, and then finally made into a steel shell, aluminum shell or aluminum-plastic film lithium battery.

[0053] Furthermore, from the above discussion, it can be seen that the liquid storage device installed inside the winding core can be universally used in wound batteries. In stacked batteries, the liquid storage device can also be evenly placed in the middle of the stacked battery. At the same time, the shape of the liquid storage device needs to be made into a cuboid or a cube; this can better stack the batteries and adapt to stacked batteries.

[0054] Embodiment 3

[0055] Please refer to Figure 1 Embodiment 3 of the present invention provides a method for manufacturing a lithium battery including the liquid storage device described in Embodiment 2, comprising the following steps:

[0056] Step S1: According to the general method for making a wound lithium battery, prepare a positive electrode sheet, a negative electrode sheet and a separator for standby use.

[0057] Step S2: fix the first liquid storage component 1 and the second liquid storage component 2 on the first winding needle 3 and the second winding needle 4 respectively; insert the first winding needle 3 into the first winding needle hole 103 in the first liquid storage component 1; and fix the first liquid storage component 1 through the first winding needle piston part 302; insert the second winding needle 4 into the second winding needle hole 203 in the second liquid storage component 2; and fix the second liquid storage component 2 through the second winding needle piston part 402.

[0058] Step S3: clamp the positive electrode sheet, the negative electrode sheet and one end of the separator between the first liquid storage member 1 and the second liquid storage member 2; and perform preparation before winding.

[0059] Step S4: driving the first winding needle 3 and the second winding needle 4 to rotate, so as to wind the positive electrode sheet, the negative electrode sheet and the separator into a winding core.

[0060] Step S5: Pull out the first winding needle 3 and the second winding needle 4 from the first liquid storage component 1 and the second liquid storage component 2 respectively, while retaining the first liquid storage component 1 and the second liquid storage component 2 inside the winding core; after the winding core is completed, retain the first liquid storage component 1 and the second liquid storage component 2 inside the winding core, thereby increasing the electrolyte retention amount and further increasing the cycle life of the lithium battery.

[0061] Step S6: Encapsulate the coil core with a steel shell, an aluminum shell or an aluminum-plastic film to produce a steel shell, an aluminum shell or an aluminum-plastic film lithium battery.

[0062] Example

[0063] The following are specific examples in actual operation, and are compared with comparative examples; the specific implementation methods are described in detail below.

[0064] First, the positive electrode sheet, negative electrode sheet and separator for winding are prepared.

[0065] The first liquid storage member 1 is fixedly mounted on the first winding needle 3 , and the first liquid storage member 1 is fixed by the first winding needle piston portion 302 .

[0066] The second liquid storage member 2 is fixedly mounted on the second winding needle 4 , and the second liquid storage member 2 is fixed by the second winding needle piston portion 402 .

[0067] The surfaces of the first liquid storage member 1 and the second liquid storage member 2 are respectively provided with a plurality of first liquid storage holes 102 and second liquid storage holes 202 , and all of them are through holes, and the diameter of the through holes is 1 mm.

[0068] The first liquid storage member 1 and the second liquid storage member 2 have a first needle hole 103 and a second needle hole 203 on one side respectively; the diameters of the first needle hole 103 and the second needle hole 203 are 2 mm.

[0069] The first liquid storage component 1 and the second liquid storage component 2 are completely identical.

[0070] The first liquid storage member 1 and the second liquid storage member 2 clamp the positive electrode sheet, the negative electrode sheet and one end of the diaphragm; drive the first winding needle 3 and the second winding needle 4 to rotate, so as to wind the positive electrode sheet, the negative electrode sheet and the diaphragm into a winding core.

[0071] After the core is rolled, the internal air pressure of the first winding needle 3 and the second winding needle 4 is released, and the pistons on the first winding needle piston part 302 and the second winding needle piston part 402 are contracted to pull the first winding needle 3 and the second winding needle 4 out of the first liquid storage part 1 and the second liquid storage part 2 respectively, while the first liquid storage part 1 and the second liquid storage part 2 are retained inside the core; after the core is rolled, the first liquid storage part 1 and the second liquid storage part 2 are retained inside the core, thereby increasing the electrolyte retention amount and further increasing the cycle life of the lithium battery.

[0072] Then the subsequent process flow is carried out according to the conventional lithium battery manufacturing process.

[0073] The coil core is encapsulated with a steel shell, an aluminum shell or an aluminum-plastic film, and finally a steel shell, an aluminum shell or an aluminum-plastic film lithium battery with a liquid storage device is manufactured; and the lithium battery of the embodiment is obtained.

[0074] Comparative Example

[0075] The comparative lithium battery is a conventional lithium battery, in which no liquid storage component is installed inside the winding core, and other designs or manufacturing processes are exactly the same as those in the embodiment.

[0076] like Figure 2 As shown, it is a comparison diagram of the cycle curves of the lithium battery of the embodiment of the present invention and the lithium battery of the comparative example; according to Figure 2 As shown, when the number of cycles is less than 800, the capacity retention rate of the lithium battery of the embodiment is better than that of the lithium battery of the comparison example, but the difference between the two is not large, and the advantage of the lithium battery of the embodiment is not very obvious; when the number of cycles is greater than 800, the capacity retention rate of the lithium battery of the embodiment is significantly better than that of the lithium battery of the comparison example. Specifically, the capacity retention rate of the lithium battery of the comparison example shows a cliff-like decline, while the capacity retention rate of the lithium battery of the embodiment maintains a stable downward trend. When the application situation requires a number of cycles greater than 800, the lithium battery of the embodiment has obvious advantages.

[0077] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A liquid storage device, characterized in that: The invention comprises at least a first liquid storage member (1) and a second liquid storage member (2), wherein the structures of the first liquid storage member (1) and the second liquid storage member (2) are completely the same, and the first liquid storage member (1) is arranged above the second liquid storage member (2); both the first liquid storage member (1) and the second liquid storage member (2) store electrolyte; the first liquid storage member (1) comprises a first liquid storage member body (101), a first liquid storage hole (102) for circulating or storing electrolyte, and a first needle winding hole (103) for accommodating a first winding needle (3); the first needle winding hole (3) is used to drive the first liquid storage member (1) to perform rotational movement; the second liquid storage member (2) comprises a second liquid storage member body (201), a second liquid storage hole (202) for circulating or storing electrolyte, and a second needle winding hole (203) for accommodating a second needle winding hole (4); the second needle winding hole (4) is used to drive the second liquid storage member (2) to perform rotational movement; The first liquid storage hole (102) is a through hole for electrolyte circulation or a blind hole for electrolyte storage; the number of the first liquid storage hole (102) is at least one; the diameter of the first liquid storage hole (102) is between 0.5 and 3 mm; the second liquid storage hole (202) is a through hole for electrolyte circulation or a blind hole for electrolyte storage; the number of the second liquid storage hole (202) is at least one; the diameter of the second liquid storage hole (202) is between 0.5 and 3 mm; The first liquid storage element (1) and the second liquid storage element (2) are in a semi-cylindrical shape or a semi-elliptical cylinder shape; The first winding needle (3) comprises a first winding needle body (303) and a first winding needle insertion portion (301) mounted at one end of the first winding needle body (303); the first winding needle insertion portion (301) is also mounted with a first winding needle piston portion (302); the first winding needle insertion portion (301) is inserted into the first winding needle hole (103); the first winding needle piston portion (302) is in close contact with the first winding needle hole (103), thereby driving the first liquid storage member (1) to perform a rotational motion; The second winding needle (4) comprises a second winding needle body (403) and a second winding needle insertion portion (401) mounted at one end of the second winding needle body (403); the second winding needle insertion portion (401) is further mounted with a second winding needle piston portion (402); the second winding needle insertion portion (401) is inserted into the second winding needle hole (203); the second winding needle piston portion (402) is in close contact with the second winding needle hole (203), thereby driving the second liquid storage member (2) to perform rotational movement.

2. A liquid storage device according to claim 1, characterized in that: The number of the first roll pinhole (103) and the second roll pinhole (203) is at least one; and the diameters of the first roll pinhole (103) and the second roll pinhole (203) are between 1 and 5 mm.

3. A liquid storage device according to claim 1, characterized in that: The first liquid storage member (1) and the second liquid storage member (2) are polymer material components made of polyethylene, polypropylene, polyethylene terephthalate or polycarbonate polymers that are resistant to electrolyte corrosion.

4. A lithium battery comprising a liquid storage device as claimed in any one of claims 1 to 3, characterized in that: The invention comprises a winding core, the winding core comprises a positive electrode sheet, a negative electrode sheet and a separator, and is wound by the positive electrode sheet, the negative electrode sheet and the separator, the first liquid storage component (1) and the second liquid storage component (2) clamp one end of the positive electrode sheet, the negative electrode sheet and the separator in the middle, and the liquid storage device is installed inside the winding core.

5. A lithium battery comprising the liquid storage device according to claim 4, characterized in that: The winding core is encapsulated by a steel shell, an aluminum shell or an aluminum-plastic film to produce a steel shell, an aluminum shell or an aluminum-plastic film lithium battery.

6. A method for manufacturing a lithium battery comprising the liquid storage device as claimed in claim 4, characterized in that: The following steps are involved: Step S1: preparing a positive electrode sheet, a negative electrode sheet and a separator; Step S2: inserting the first winding needle (3) into the first winding needle hole (103) in the first liquid storage component (1); and fixing the first liquid storage component (1) by means of the first winding needle piston portion (302); inserting the second winding needle (4) into the second winding needle hole (203) in the second liquid storage component (2); and fixing the second liquid storage component (2) by means of the second winding needle piston portion (402); Step S3: clamping the positive electrode sheet, the negative electrode sheet and one end of the separator between the first liquid storage member (1) and the second liquid storage member (2); Step S4: driving the first winding needle (3) and the second winding needle (4) to rotate, thereby winding the positive electrode sheet, the negative electrode sheet and the separator into a winding core; Step S5: pulling out the first winding needle (3) and the second winding needle (4) from the first liquid storage member (1) and the second liquid storage member (2) respectively, while retaining the first liquid storage member (1) and the second liquid storage member (2) inside the winding core; Step S6: Encapsulate the coil core with a steel shell, an aluminum shell or an aluminum-plastic film to produce a steel shell, an aluminum shell or an aluminum-plastic film lithium battery.

Images