Lithium ion battery deformation early warning method and device, electronic equipment and lithium ion battery

Abstract

The invention belongs to the field of lithium ion batteries, and particularly relates to a lithium ion battery deformation early warning method and device, electronic equipment and a lithium ion battery. The early warning method comprises the following steps: calculating a solubility parameter delta s of an electrolyte solvent; judging that delta s-delta g is less than or equal to 1.5 or delta s-delta j is less than or equal to 1.5, if so, triggering early warning and executing the step 4, and if not, executing the step 5; according to the battery deformation early warning method for the lithium ion battery, the solubility parameter delta s of the electrolyte solvent is calculated and is compared with the solubility parameter delta s of the electrolyte solvent and the solubility parameter delta g of the diaphragm binder, so that whether the appearance of the battery is poor or not is quickly judged; the problem of poor appearance of the battery can be timely found and prevented.

Description

Technical Field

[0001] The present invention belongs to the field of lithium-ion batteries, and particularly relates to a method and device for warning of lithium-ion battery deformation, an electronic device, and a lithium-ion battery. Background Art

[0002] The processing technology of power lithium-ion battery cells mostly adopts a fully automatic winding process. Compared with the stacking process, the winding process has higher production efficiency, lower risk of introducing burrs, more precise control of the cell coating size, and higher battery safety performance. However, during the use of wound lithium-ion batteries, appearance defects such as twisting and deformation are likely to occur, which not only affects the battery's performance but also may lead to potential safety hazards in the battery.

[0003] To solve this problem, CN108536991A provides an optimized design process for the winding tension of square lithium-ion batteries, which is optimized from the perspective of mechanical structure. However, this method mainly relies on the adjustment of process parameters and is complex to operate. CN117019645A provides a micro-deformation detection device for square shell lithium-ion batteries, but this method has the defects of physical detection lag and high cost. Currently, in addition to winding tension and electrode expansion, another main reason for the twisting and deformation problem of wound-structured lithium-ion batteries is the dissolution or swelling caused by the electrode binder and the separator coating binder reacting with the electrolyte solvent, and there is still a blank in the technical methods for improvement from this perspective. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings in the prior art and provide a method and device for warning of lithium-ion battery deformation, an electronic device, and a lithium-ion battery.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for warning of lithium-ion battery deformation includes the following steps:

[0007] Step 1: Calculate the solubility parameter δs of the electrolyte solvent;

[0008] Step 2: Compare the calculated solubility parameter δs of the electrolyte solvent with the solubility parameter δg of the separator binder or the solubility parameter δj of the electrode binder;

[0009] Step 3: Determine whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5. If so, trigger a warning and execute Step 4; if not, execute Step 5;

[0010] Step 4: Determine that there is a risk of battery deformation caused by the dissolution of the separator binder or the electrode binder, adjust the electrolyte solvent ratio; execute Step 1, and recalculate the solubility parameter δs of the adjusted electrolyte solvent;

[0011] Step 5: Determine that the battery is not prone to appearance defects such as distortion and deformation.

[0012] In Step 1, δs = Σ(δi × φi), where φi is the volume fraction of solvent component i, and δi is the solubility parameter of solvent component i.

[0013] The electrode binder and the separator binder are independently PVDF; preferably, δj = 22.5 and δg = 22.5.

[0014] In Step 3, determine whether δs ∈ [21, 24]. If so, trigger an alarm and execute Step 4; if not, execute Step 5.

[0015] The present invention further includes a lithium-ion battery deformation warning device, comprising:

[0016] A deformation warning parameter determination module, configured to determine the solubility parameter δs of the electrolyte solvent, the solubility parameter δg of the separator binder, or the solubility parameter δj of the electrode binder;

[0017] A deformation warning judgment module, configured to compare according to the data of the deformation warning parameter determination module to determine whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5 is met;

[0018] A warning message sending module, configured to send a corresponding warning message according to the deformation warning judgment module.

[0019] The present invention further includes an electronic device, comprising a memory and a processor, where the memory stores computer instructions, and the computer instructions, when executed by the processor, implement the lithium-ion battery deformation warning method.

[0020] The present invention further includes a lithium-ion battery obtained by controlling the solubility parameter δs of the electrolyte according to the lithium-ion battery deformation warning method.

[0021] The lithium-ion battery includes electrodes, a separator, and an electrolyte; the separator coating contains a separator binder; the electrode contains an electrode binder; the solubility parameter of the electrolyte is δs, and |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5; where δg is the solubility parameter of the separator binder, and δj is the solubility parameter of the electrode binder.

[0022] The electrode binder and the separator binder are independently PVDF; preferably, δj = 22.5 and δg = 22.5.

[0023] The calculation formula for the solubility parameter δs of the electrolyte is that the solubility parameter is δs ∈ [21, 24].

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The method for warning of lithium-ion battery deformation of the present invention calculates the solubility parameter δs of the electrolyte solvent, and compares it with the solubility parameter δj of the electrode binder and the solubility parameter δg of the separator binder to quickly judge whether the battery is prone to appearance defects, and can timely detect and prevent the appearance defects of the battery. At the same time, by adjusting the electrolyte solvent ratio to prepare a suitable lithium-ion battery with the solubility parameter of the solvent, it is possible to avoid the swelling or dissolution of the binder in the electrolyte, resulting in battery deformation, effectively solving the problem of poor battery appearance, and improving the energy density and cycle life of the lithium-ion battery. Description of the Drawings

[0026] Figure 1 is the logic flow chart of the method for warning of lithium-ion battery deformation;

[0027] Figure 2 is the box plot of the battery thickness in the examples using EL01 and EL02 electrolytes;

[0028] Figure 3 is the trend chart of the cyclic thickness change of the batteries using EL01 and EL02 electrolytes in the examples;

[0029] Figure 4 is the diagram of wiping the separator coating with dimethyl carbonate (DMC), EL01, and EL02 respectively in the examples. Detailed Embodiments

[0030] In order to enable those skilled in the art of the present technology to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the drawings and the best embodiments.

[0031] Example 1

[0032] A method for warning of lithium-ion battery deformation ( Figure 1 shown) includes the following steps:

[0033] Step 1. Calculate the solubility parameter δs of the EL01 electrolyte solvent.

[0034] Step 101. According to the composition of the electrolyte solvent, look up the solubility parameters δ1, δ2,... of each solvent component. The EL01 electrolyte solvent is composed of ethylene carbonate (δ1 = 29.6), propylene carbonate (δ2 = 27.3), diethyl carbonate (δ3 = 17.9), and propyl propionate (δ4 = 17.3).

[0035] Step 102: Calculate the volume fractions φ1, φ2, ... of each solvent component. The volume fraction φ1 of ethylene carbonate is 0.2, the volume fraction φ2 of propylene carbonate is 0.2, the volume fraction φ3 of diethyl carbonate is 0.3, and the volume fraction φ4 of propyl propionate is 0.3.

[0036] Step 103: Substitute the results of Step 101 and Step 102 into the formula δs = Σ(δi × φi) to calculate the solubility parameter δs of the EL01 electrolyte solvent. δs = 0.2 × 29.6 + 0.2 × 27.3 + 0.3 × 17.9 + 0.3 × 17.3 = 21.94.

[0037] Step 2: Compare the calculated solubility parameter δs = 21.94 of the EL01 electrolyte solvent with the solubility parameter 22.5 of polyvinylidene fluoride (PVDF).

[0038] Step 3: Judge whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5, that is, δs = 21.94 is in the range of 21 - 24: Yes, trigger a warning, adjust the electrolyte solution ratio, and execute Step 4.

[0039] Step 4: When δs ∈ [21, 24], it is determined that there is a risk of electrode deformation caused by PVDF dissolution.

[0040] Adjust the electrolyte solvent ratio to EL02 electrolyte. Re - execute Step 1.

[0041] Step 1: Calculate the solubility parameter δs of the EL02 electrolyte solvent.

[0042] Step 101: According to the composition of the electrolyte solvent, look up the solubility parameters δ1, δ2, ... of each solvent component. The EL02 electrolyte solvent consists of ethylene carbonate (δ1 = 29.6), propylene carbonate (δ2 = 27.3), diethyl carbonate (δ3 = 17.9), and propyl propionate (δ4 = 17.3).

[0043] Step 102: Calculate the volume fractions φ1, φ2, ... of each solvent component. The volume fraction φ1 of ethylene carbonate is 0.05, the volume fraction φ2 of propylene carbonate is 0.2, the volume fraction φ3 of diethyl carbonate is 0.25, and the volume fraction φ4 of propyl propionate is 0.5.

[0044] Step 103: Substitute the results of Step 101 and Step 102 into the formula δs = Σ(δi × φi) to calculate the solubility parameter δs of the EL02 electrolyte solvent. δs = 0.05 × 29.6 + 0.2 × 27.3 + 0.25 × 17.9 + 0.5 × 17.3 = 20.07.

[0045] Step 2: Compare the calculated solubility parameter δs = 20.07 of the EL02 electrolyte solvent with the solubility parameter 22.5 of polyvinylidene fluoride (PVDF).

[0046] Step 3: Judge whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5, that is, δs = 21.94 is within the range of 21 - 24: No, execute Step 5.

[0047] Step 5: When δs = 20.07 does not belong to (21, 24), judge that the battery is not likely to have appearance defects such as distortion and deformation.

[0048] Step 6: During the battery production process, adopt the adjusted EL02 electrolyte solvent ratio to make the solubility parameter δ of the electrolyte solvent not within the range of 21 - 24, so as to prevent the battery from having appearance defects such as distortion and deformation.

[0049] Form a battery with the electrolyte, the electrode sheet containing the binder, and the separator according to the conventional process. Figure 2 It is the box plot of the battery thickness of applying EL01 and EL02 electrolytes in the embodiment. Figure 3 It is the trend chart of the cyclic thickness change of the battery applying EL01 and EL02 electrolytes in the embodiment. Figure 4 It is the diagram of wiping the separator coating using dimethyl carbonate (DMC), EL01, and EL02 respectively in the embodiment. The results show that the diagrams of wiping the separator coating with EL01 and EL02 are consistent with the box plot of the thickness and the trend chart of the cyclic thickness change. The binder will swell in the electrolyte, resulting in battery deformation.

[0050] Example 2

[0051] A lithium-ion battery deformation warning device, comprising:

[0052] A deformation warning parameter determination module, used to determine the solubility parameter δs of the electrolyte solvent, the solubility parameter δg of the separator binder, or the solubility parameter δj of the electrode sheet binder;

[0053] A deformation warning judgment module, used to make a comparison according to the data of the deformation warning parameter determination module to determine whether it meets |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5;

[0054] A warning message sending module, used to send corresponding warning messages according to the deformation warning judgment module.

[0055] Example 3

[0056] An electronic device, comprising a memory and a processor, where the memory stores computer instructions, and the computer instructions, when executed by the processor, implement the above-mentioned lithium-ion battery deformation warning method.

[0057] Example 4

[0058] A lithium-ion battery obtained by controlling the solubility parameter δs of the electrolyte according to the lithium-ion battery deformation warning method described above, comprising a pole piece, a separator, and an electrolyte

[0059] The separator coating contains a separator binder; the pole piece contains a pole piece binder; the solubility parameter of the electrolyte is δs, |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5; wherein, δg is the solubility parameter of the separator binder, and δj is the solubility parameter of the pole piece binder. The pole piece binder and the separator binder are independently PVDF; δj = 22.5, δg = 22.5. The calculation formula for the solubility parameter δs of the electrolyte is solubility parameter δs = Σ(δi × φi).

[0060] The electrolyte solvent consists of ethylene carbonate (δ1 = 29.6), propylene carbonate (δ2 = 27.3), diethyl carbonate (δ3 = 17.9), and propyl propionate (δ4 = 17.3). The volume fraction of ethylene carbonate φ1 = 0.05, the volume fraction of propylene carbonate φ2 = 0.2, the volume fraction of diethyl carbonate φ3 = 0.25, and the volume fraction of propyl propionate φ4 = 0.5;

[0061] δs = 0.05 × 29.6 + 0.2 × 27.3 + 0.25 × 17.9 + 0.5 × 17.3 = 20.07;

[0062] When δs = |20.07 - 22.5| > 1.5, that is, when δs does not belong to (21, 24), it is judged that the battery is not likely to have appearance defects such as twisting deformation.

[0063] In summary, by using the lithium-ion battery deformation warning method of the present application, by calculating the solubility parameter δs of the electrolyte solvent and comparing it with the solubility parameter δg of the separator binder of the electrolyte solvent, it is possible to quickly judge whether the battery is likely to have appearance defects, and timely discover and prevent battery appearance defect problems. At the same time, by adjusting the electrolyte solvent ratio to make the solubility parameter of the solvent, a suitable lithium-ion battery can be prepared, which can avoid the swelling or dissolution of the binder in the electrolyte, resulting in battery deformation, effectively solve the battery appearance defect problem, and improve the energy density and cycle life of the lithium-ion battery.

[0064] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can still be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A method for warning of deformation of a lithium-ion battery, characterized in that, It includes the following steps: Step 1: Calculate the solubility parameter δs of the electrolyte solvent; Step 2: Compare the calculated solubility parameter δs of the electrolyte solvent with the solubility parameter δg of the separator binder or the solubility parameter δj of the electrode binder; Step 3: Judge whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.

5. If so, trigger an early warning and execute Step 4. If not, execute Step 5; Step 4: Determine that there is a risk of battery deformation caused by the dissolution of the separator binder or the electrode binder, adjust the electrolyte solvent ratio; execute Step 1, and recalculate the solubility parameter δs of the adjusted electrolyte solvent; Step 5: Judge that the battery is not prone to the appearance defect of twisting deformation.

2. The method for warning of deformation of a lithium-ion battery according to claim 1, wherein In Step 1, δs = Σ(δi × φi), where φi is the volume fraction of solvent component i, and δi is the solubility parameter of solvent component i.

3. The method for warning of deformation of a lithium-ion battery according to claim 1, characterized in that, The electrode binder and the separator binder are independently PVDF; preferably, δj = 22.5 and δg = 22.

5.

4. The method for warning of lithium-ion battery deformation according to claim 3, wherein In Step 3, judge whether δs ∈ [21, 24]. If so, trigger an early warning and execute Step 4. If not, execute Step 5.

5. A deformation warning device for a lithium-ion battery, characterized in that, It includes: A deformation early warning parameter determination module for determining the solubility parameter δs of the electrolyte solvent, the solubility parameter δg of the separator binder, and the solubility parameter δj of the electrode binder; A deformation early warning judgment module for comparing according to the data of the deformation early warning parameter determination module to determine whether |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5 is met; A warning message sending module for sending corresponding warning messages according to the deformation early warning judgment module.

6. An electronic device, characterized in that, It includes a memory and a processor. The memory stores computer instructions, and when the computer instructions are executed by the processor, the lithium-ion battery deformation early warning method described in any one of Claims 1-4 is implemented.

7. A lithium-ion battery, characterized in that, The solubility parameter δs of the electrolyte is obtained by controlling according to the lithium-ion battery deformation early warning method described in any one of Claims 1-4.

8. The lithium-ion battery according to claim 7, wherein, It includes an electrode, a separator, and an electrolyte; the separator coating contains a separator binder; the electrode contains an electrode binder; the solubility parameter of the electrolyte is δs, and |δs - δg| ≤ 1.5 or |δs - δj| ≤ 1.5; where δg is the solubility parameter of the separator binder and δj is the solubility parameter of the electrode binder.

9. The lithium-ion battery according to claim 7, characterized in that, The electrode binder and the separator binder are independently PVDF; preferably, δj = 22.5 and δg = 22.

5.

10. The lithium-ion battery according to claim 7, wherein δs ∈ [21, 24].

Images