Modified carboxymethylcellulose salt, cathode dispersant, cathode sheet, battery cell, battery and electric device

Abstract

The present invention provides a modified carboxymethylcellulose salt, a cathode dispersant, a cathode sheet, a battery cell, a battery, and an electric device. The battery cell comprises a cathode sheet, wherein the cathode sheet comprises a cathode current collector and a cathode film layer installed on at least one side of the cathode current collector, wherein the cathode film layer comprises a cathode active material and a cathode dispersant, wherein the cathode dispersant comprises a modified carboxymethylcellulose salt, and the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A, wherein in Formula A, Q comprises a hydrogen atom or -CH2COOM1, M1 comprises at least one of a metal ion or NH4+; and R comprises a hydrogen atom or a flexible group, wherein the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group. The cathode film layer has relatively good flexibility and does not crack easily. Formula A

Description

Technology Field

[0001] This application claims priority to Chinese Patent Application 202410823161.4, filed on June 24, 2024, titled "Modified Carboxymethylcellulose Salt, Cathode Dispersant, Cathode Sheet, Battery Cell, Battery and Electric Device," the entire contents of which are incorporated herein by reference.

[0002] The present application relates to a modified carboxymethylcellulose salt, a cathode dispersant, a cathode sheet, a battery cell, a battery, and an electric device. Background Technology

[0004] Battery cells are being widely applied due to their advantages, such as reliable operating performance, zero emissions, and memory-free effects. For example, as environmental protection becomes increasingly important, new energy vehicles are becoming more widespread, leading to an explosive increase in demand for power battery cells.

[0005] As the range of applications for batteries expands, requirements for battery performance are becoming increasingly stringent. However, due to the risk of cracking in the cathode sheet during the manufacturing process, the cathode sheet performance cannot meet production requirements. The problem to be solved

[0007] The present application aims to provide a modified carboxymethylcellulose salt, a cathode dispersant, a cathode sheet, a battery cell, a battery, and an electric device.

[0008] The present application provides a modified carboxymethylcellulose salt, a cathode dispersant, a cathode sheet, a battery cell, a battery, and an electric device, and the present application can reduce the risk of cracking in the cathode film layer of the cathode sheet. means of solving the problem

[0010] In a first embodiment, the present application proposes a battery cell, wherein the battery cell comprises a negative electrode sheet, the negative electrode sheet comprises a negative current collector and a negative film layer installed on at least one side of the negative current collector, the negative film layer comprises a negative active material and a negative dispersant, the negative dispersant comprises a modified carboxymethylcellulose salt, and the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A.

[0011] Formula A,

[0012] In Equation A,

[0013] Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + Includes at least one of the following;

[0014] R comprises a hydrogen atom or a flexible group, and the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group.

[0015] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-1.

[0016] Formula A-1

[0017] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-2.

[0018] Formula A-2

[0019] In some embodiments, the cathodic dispersant further comprises a structural unit represented by Formula B, and

[0020] Formula B,

[0021] In Equation B,

[0022] M2 is metal ions or NH4 +Includes at least one of them.

[0023] In some embodiments, based on the total quantity of structural units represented by Formula A and structural units represented by Formula B, the quantity share of the structural unit represented by Formula A is 0.5% to 20%, optionally 1% to 10%.

[0024] In some embodiments, the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group. The above-mentioned group can improve the flexibility of the cathode film layer by enabling the modified carboxymethylcellulose salt to have excellent flexibility.

[0025] In some embodiments, the substituted or unsubstituted C3 to C150 ether groups comprise the structural formula represented by Formula 1, and

[0026] Equation 1,

[0027] In Equation 1,

[0028] R 11 to R 17 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0029] m includes any positive integer from 5 to 60.

[0030] In some embodiments, the substituted or unsubstituted C3 to C150 ether group comprises at least one of the structural formulas represented by Formula 1-1 to Formula 1-14, and

[0031] Equation 1-1, Equation 1-2,

[0032] Equation 1-3, Equation 1-4,

[0033] Equation 1-5,

[0034] Equation 1-6,

[0035] Equation 1-7, Equation 1-8,

[0036] Equation 1-9, Equation 1-10, Equation 1-11, Equation 1-12, Equation 1-13, Equation 1-14,

[0037] Here, m1 includes any positive integer from 1 to 30.

[0038] In some embodiments, the substituted or unsubstituted C3 to C150 alkyl group comprises the structural formula represented by Formula 2, and

[0039] Equation 2,

[0040] In Equation 2,

[0041] R 21 to R 27 Each independently comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0042] s includes any positive integer from 5 to 60.

[0043] In some embodiments, the substituted or unsubstituted C3 to C150 alkyl group comprises at least one of the structural formulas represented by Formula 2-1 to Formula 2-11, and

[0044] Equation 2-1, Equation 2-2,

[0045] Equation 2-3, Equation 2-4,

[0046] Equation 2-5,

[0047] Equation 2-6, Equation 2-7,

[0048] Equation 2-8, Equation 2-9,

[0049] Equation 2-10, Equation 2-11,

[0050] Here, s1 includes any positive integer from 1 to 30.

[0051] In some embodiments, the substituted or unsubstituted C3 to C150 polyolefin group comprises the structural formula represented by Formula 3, and

[0052] Equation 3,

[0053] In Equation 3,

[0054] R 31 to R 34 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C2 to C10 alkenyl group;

[0055] R 35 It comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0056] p includes any positive integer from 5 to 60.

[0057] In some embodiments, the substituted or unsubstituted C3 to C150 polyolefin group comprises at least one of the structural formulas represented by Formula 3-1 to Formula 3-8.

[0058] Equation 3-1, Equation 3-2, Equation 3-3, Equation 3-4, Equation 3-5, Equation 3-6,

[0059] Equation 3-7, Equation 3-8

[0060] In some embodiments, the substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4, and

[0061] Equation 4,

[0062] In Equation 4,

[0063] R 41 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0064] R 42 to R 46 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0065] a includes any positive integer from 1 to 30.

[0066] In some embodiments, R 41 The C3 to C150 amide group comprises a single bond and has a substituted or unsubstituted structure formula represented by Formula 4-1.

[0067] Equation 4-1

[0068] In some embodiments, the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-11 to Formula 4-15.

[0069] Equation 4-11, Equation 4-12,

[0070] Equation 4-13, Equation 4-14,

[0071] Equation 4-15

[0072] In some embodiments, R 41 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4-2,

[0073] Equation 4-2,

[0074] a1 includes any positive integer from 1 to 5.

[0075] In some embodiments, the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-21 to Formula 4-24.

[0076] Equation 4-21, Equation 4-22, Equation 4-23, Equation 4-24

[0077] In some embodiments, the substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5, and

[0078] Equation 5,

[0079] In Equation 5,

[0080] R 51 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0081] R 52 It comprises substituted or unsubstituted C1 to C5 alkyl groups;

[0082] R 53 to R 55 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0083] b includes any positive integer from 1 to 30.

[0084] In some embodiments, R51 comprises a single bond, and the substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5-1.

[0085] Equation 5-1

[0086] In some embodiments, the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-11 to Formula 5-16.

[0087] Equation 5-11, Equation 5-12, Equation 5-13, Equation 5-14, Equation 5-15, Equation 5-16

[0088] In some embodiments, R 51 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5-2,

[0089] Equation 5-2,

[0090] b1 includes any positive integer from 1 to 5.

[0091] In some embodiments, the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-21 to Formula 5-28.

[0092] Equation 5-21, Equation 5-22, Equation 5-23, Equation 5-24,

[0093] Equation 5-25, Equation 5-26,

[0094] Equation 5-27, Equation 5-28

[0095] In some embodiments, the weight average molecular weight of the cathodic dispersant is 40 wDa to 80 wDa. When the weight average molecular weight of the modified carboxymethylcellulose salt is within the range described above, the cathodic dispersant can be made to have excellent dispersion performance.

[0096] In some embodiments, the elongation at break of the reference adhesive film made of sodium carboxymethylcellulose is 100%, the elongation at break of the adhesive film made of modified carboxymethylcellulose salt is 225% to 400%, and the width of the adhesive film made of the cathodic dispersant and the reference adhesive film is 2.5 cm, the length is 5 cm, and the thickness is 1 mm.

[0097] In some embodiments, the mass content of the cathode dispersant is 0.8% to 1.3% based on the total mass of the cathode film layer, optionally 1.0% to 1.2%. When the mass content of the cathode dispersant is within the above-described range, the flexibility of the cathode film layer can be effectively improved, the dispersion of the cathode active material in the cathode film layer is relatively uniform, and the performance of the cathode film layer is relatively uniform.

[0098] In some embodiments, the coating basis weight of the cathode film layer is 200 mg / 1540.25 mm 2 Up to 280 mg / 1540.25 mm 2 ; Optionally 220mg / 1540.25mm 2 Up to 280 mg / 1540.25 mm 2 It is. Since the coating basis weight of the cathode film layer is relatively high, it is advantageous for implementing a thick coating.

[0099] In a second aspect, the present application proposes a cathodic dispersant, wherein the cathodic dispersant comprises a modified carboxymethylcellulose salt, and the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A,

[0100] Formula A,

[0101] In Equation A,

[0102] Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + Includes at least one of the following;

[0103] R comprises a hydrogen atom or a flexible group, and the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group.

[0104] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-1.

[0105] Formula A-1

[0106] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-2.

[0107] Formula A-2

[0108] In some embodiments, the cathodic dispersant further comprises a structural unit represented by Formula B, and

[0109] Formula B,

[0110] In Equation B,

[0111] M2 is metal ions or NH4 + Includes at least one of them.

[0112] In some embodiments, based on the total quantity of structural units represented by Formula A and structural units represented by Formula B, the quantity share of the structural unit represented by Formula A is 0.5% to 20%, optionally 1% to 10%.

[0113] In some embodiments, the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group. The above-mentioned group can improve the flexibility of the cathode film layer by enabling the modified carboxymethylcellulose salt to have excellent flexibility.

[0114] In some embodiments, the substituted or unsubstituted C3 to C150 ether groups comprise the structural formula represented by Formula 1, and

[0115] Equation 1,

[0116] In Equation 1,

[0117] R 11 to R 17 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0118] m includes any positive integer from 5 to 60.

[0119] In some embodiments, the substituted or unsubstituted C3 to C150 ether group comprises at least one of the structural formulas represented by Formula 1-1 to Formula 1-14, and

[0120] Equation 1-1, Equation 1-2,

[0121] Equation 1-3, Equation 1-4,

[0122] Equation 1-5,

[0123] Equation 1-6,

[0124] Equation 1-7, Equation 1-8,

[0125] Equation 1-9, Equation 1-10, Equation 1-11, Equation 1-12, Equation 1-13, Equation 1-14,

[0126] Here, m1 includes any positive integer from 1 to 30.

[0127] In some embodiments, the substituted or unsubstituted C3 to C150 alkyl group comprises the structural formula represented by Formula 2, and

[0128] Equation 2,

[0129] In Equation 2,

[0130] R 21 to R 27 Each independently comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0131] s includes any positive integer from 5 to 60.

[0132] In some embodiments, the substituted or unsubstituted C3 to C150 alkyl group comprises at least one of the structural formulas represented by Formula 2-1 to Formula 2-11, and

[0133] Equation 2-1, Equation 2-2,

[0134] Equation 2-3, Equation 2-4,

[0135] Equation 2-5,

[0136] Equation 2-6, Equation 2-7,

[0137] Equation 2-8, Equation 2-9,

[0138] Equation 2-10, Equation 2-11,

[0139] Here, s1 includes any positive integer from 1 to 30.

[0140] In some embodiments, the substituted or unsubstituted C3 to C150 polyolefin group comprises the structural formula represented by Formula 3, and

[0141] Equation 3,

[0142] In Equation 3,

[0143] R 31 to R 34 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C2 to C10 alkenyl group;

[0144] R 35 It comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0145] p includes any positive integer from 5 to 60.

[0146] In some embodiments, the substituted or unsubstituted C3 to C150 polyolefin group comprises at least one of the structural formulas represented by Formula 3-1 to Formula 3-8.

[0147] Equation 3-1, Equation 3-2, Equation 3-3, Equation 3-4, Equation 3-5, Equation 3-6,

[0148] Equation 3-7, Equation 3-8

[0149] In some embodiments, the substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4, and

[0150] Equation 4,

[0151] In Equation 4,

[0152] R 41 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0153] R 42 to R 46 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0154] a includes any positive integer from 1 to 30.

[0155] In some embodiments, R 41 The C3 to C150 amide group comprises a single bond and has a substituted or unsubstituted structure formula represented by Formula 4-1.

[0156] Equation 4-1

[0157] In some embodiments, the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-11 to Formula 4-15.

[0158] Equation 4-11, Equation 4-12,

[0159] Equation 4-13, Equation 4-14,

[0160] Equation 4-15

[0161] In some embodiments, R 41 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4-2,

[0162] Equation 4-2,

[0163] a1 includes any positive integer from 1 to 5.

[0164] In some embodiments, the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-21 to Formula 4-24.

[0165] Equation 4-21, Equation 4-22, Equation 4-23, Equation 4-24

[0166] In some embodiments, the substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5, and

[0167] Equation 5,

[0168] In Equation 5,

[0169] R 51 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0170] R 52 It comprises substituted or unsubstituted C1 to C5 alkyl groups;

[0171] R 53 to R 55 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0172] b includes any positive integer from 1 to 30.

[0173] In some embodiments, R 51 The C3 to C150 ester group, which includes a single bond, includes the structural formula represented by Formula 5-1, which is substituted or unsubstituted.

[0174] Equation 5-1

[0175] In some embodiments, the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-11 to Formula 5-16.

[0176] Equation 5-11, Equation 5-12, Equation 5-13, Equation 5-14, Equation 5-15, Equation 5-16

[0177] In some embodiments, R 51 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5-2,

[0178] Equation 5-2,

[0179] b1 includes any positive integer from 1 to 5.

[0180] In some embodiments, the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-21 to Formula 5-28.

[0181] Equation 5-21, Equation 5-22, Equation 5-23, Equation 5-24,

[0182] Equation 5-25, Equation 5-26,

[0183] Equation 5-27, Equation 5-28

[0184] In some embodiments, the weight average molecular weight of the cathodic dispersant is 40 wDa to 80 wDa. When the weight average molecular weight of the modified carboxymethylcellulose salt is within the range described above, the cathodic dispersant can be made to have excellent dispersion performance.

[0185] In some embodiments, the elongation at break of the reference adhesive film made of sodium carboxymethylcellulose is 100%, the elongation at break of the adhesive film made of modified carboxymethylcellulose salt is 225% to 400%, and the width of the adhesive film made of the cathodic dispersant and the reference adhesive film is 2.5 cm, the length is 5 cm, and the thickness is 1 mm.

[0186] In a third aspect, the present application also comprises a modified carboxymethylcellulose salt comprising a structural unit represented by Formula A, and

[0187] Formula A,

[0188] In Equation A,

[0189] Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + Includes at least one of the following;

[0190] R comprises a hydrogen atom or a flexible group, and the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group.

[0191] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-1.

[0192] Formula A-1

[0193] In some embodiments, the structural unit represented by Formula A includes the structural unit represented by Formula A-2.

[0194] Formula A-2

[0195] In some embodiments, the cathodic dispersant further comprises a structural unit represented by Formula B, and

[0196] Formula B,

[0197] In Equation B,

[0198] M2 is metal ions or NH4 + Includes at least one of them.

[0199] In some embodiments, based on the total quantity of structural units represented by Formula A and structural units represented by Formula B, the quantity share of the structural unit represented by Formula A is 0.5% to 20%, optionally 1% to 10%.

[0200] In some embodiments, the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group. The above-mentioned group can improve the flexibility of the cathode film layer by enabling the modified carboxymethylcellulose salt to have excellent flexibility.

[0201] In a fourth aspect, the present application also proposes a cathode sheet, wherein the cathode sheet comprises a cathode current collector and a cathode film layer installed on at least one surface of the cathode current collector, and the cathode film layer comprises a cathode dispersant according to any one embodiment of the second aspect of the present application.

[0202] In a fifth aspect, the embodiment of the present application also proposes a battery, the battery comprising a battery cell according to any one embodiment of the first aspect of the present application.

[0203] In a sixth aspect, an embodiment of the present application also proposes an electric device comprising a battery according to any one embodiment of the fifth aspect of the present application. Effects of the invention

[0205] Accordingly, the cathode dispersant of the embodiment of the present application comprises a modified carboxymethylcellulose salt, and the modified carboxymethylcellulose salt comprises the structural unit described above, wherein the structural unit described above increases the carbon chain length of the main chain of the modified carboxymethylcellulose salt, increases the rotationality of the main chain, and increases flexibility, thereby improving the flexibility of the modified carboxymethylcellulose salt, and thereby improving the flexibility of the cathode film layer, reducing the risk of cracking in the cathode film layer, and particularly reducing the risk of cracking in a thickly coated cathode film layer, thereby improving the energy density of the battery cell;

[0206] Additionally, the above-described structural unit further includes flexible groups, and the flexible groups can reduce the inter-molecular forces, thereby further enhancing the flexibility of the modified carboxymethylcellulose salt, improving the flexibility of the cathode film layer, and reducing the risk of cracking in the cathode film layer;

[0207] In addition, since the modified carboxymethylcellulose salt has relatively excellent dispersion and smoothing effects, it can effectively disperse the cathode active material to ensure uniform dispersion of the cathode active material, thereby making the thickness distribution of the cathode film layer uniform and ensuring uniform performance;

[0208] Accordingly, when the cathode film layer contains a modified carboxymethylcellulose salt, the flexibility of the cathode film layer is improved, the risk of cracking is relatively low, the thickness of the cathode film layer is uniform, and the performance is uniform.

[0209] Accordingly, when the quantity share of the structural unit represented by Formula A in the embodiment of the present application is within the range described above, the modified carboxymethylcellulose salt has excellent hydrophobicity, so it can have excellent dispersion action on a negative electrode active material such as graphite material and can effectively improve the flexibility of the carboxymethylcellulose salt.

[0210] Accordingly, the ether group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0211] Accordingly, the alkyl group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0212] Accordingly, the polyolefin group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0213] Accordingly, the amide group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0214] Accordingly, the ester group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0215] Accordingly, in the embodiments of the present application, the elongation at break of the cathode dispersant is higher than that of general sodium carboxymethylcellulose, and when the cathode dispersant is applied to a cathode sheet, the flexibility is relatively excellent and it does not break easily.

[0216] Accordingly, the cathode dispersant of the embodiment of the present application comprises a modified carboxymethylcellulose salt comprising the structural unit described above, wherein the structural unit described above increases the carbon chain length of the main chain of the modified carboxymethylcellulose salt, increases the rotationality of the main chain, and increases flexibility, thereby improving the flexibility of the modified carboxymethylcellulose salt, thereby improving the flexibility of the cathode film layer, reducing the risk of cracking in the cathode film layer, and particularly reducing the risk of cracking in a thickly coated cathode film layer, thereby improving the energy density of the battery cell; additionally, the structural unit described above further comprises a flexible group, wherein the flexible group can reduce the interaction force between molecular chains, thereby further improving the flexibility of the modified carboxymethylcellulose salt, improving the flexibility of the cathode film layer, and reducing the risk of cracking in the cathode film layer; In addition, since the modified carboxymethylcellulose salt has relatively excellent dispersion and smoothing effects, it can effectively disperse the cathode active material so that the cathode active material is uniformly dispersed, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform; accordingly, when the cathode film layer contains the modified carboxymethylcellulose salt, the flexibility of the cathode film layer is improved, the risk of cracking is relatively low, the thickness of the cathode film layer is uniform, and the performance is uniform.

[0217] Accordingly, when the quantity share of the structural unit represented by Formula A in the embodiment of the present application is within the range described above, the modified carboxymethylcellulose salt has excellent hydrophobicity, so it can have excellent dispersion action on a negative electrode active material such as graphite material and can effectively improve the flexibility of the carboxymethylcellulose salt.

[0218] Accordingly, the ether group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0219] Accordingly, the alkyl group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0220] Accordingly, the polyolefin group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0221] Accordingly, the amide group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0222] Accordingly, the ester group can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0223] Accordingly, in the embodiments of the present application, the elongation at break of the cathode dispersant is higher than that of general sodium carboxymethylcellulose, and when the cathode dispersant is applied to a cathode sheet, the flexibility is relatively excellent and it does not break easily.

[0224] Accordingly, the modified carboxymethylcellulose salt of the embodiment of the present application comprises the structural unit described above, and the structural unit described above can increase the carbon chain length of the main chain of the modified carboxymethylcellulose salt, increase the rotationality of the main chain, and increase flexibility, thereby improving the flexibility of the modified carboxymethylcellulose salt, and when applied to a cathode film layer, can improve the flexibility of the cathode film layer, reduce the risk of cracking in the cathode film layer, and particularly reduce the risk of cracking in a thickly coated cathode film layer, thereby improving the energy density of the battery cell; additionally, the structural unit described above further comprises a flexible group, and the flexible group can weaken the hydrogen bonding between the molecular chains of the modified carboxymethylcellulose salt, thereby reducing the interaction force between the molecular chains, thereby further improving the flexibility of the modified carboxymethylcellulose salt, improving the flexibility of the cathode film layer, and reducing the risk of cracking in the cathode film layer; In addition, since the modified carboxymethylcellulose salt has relatively excellent dispersion and smoothing effects, it can effectively disperse the cathode active material so that the cathode active material is uniformly dispersed, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform; accordingly, when the cathode film layer contains the modified carboxymethylcellulose salt, the flexibility of the cathode film layer is improved, the risk of cracking is relatively low, the thickness of the cathode film layer is uniform, and the performance is uniform.

[0225] Accordingly, when the quantity share of the structural unit represented by Formula A in the embodiment of the present application is within the range described above, the modified carboxymethylcellulose salt has excellent hydrophobicity, so it can have excellent dispersion action on a negative electrode active material such as graphite material and can effectively improve the flexibility of the carboxymethylcellulose salt. Brief explanation of the drawing

[0227] To further clarify the technical solution of the embodiments of the present application, the drawings to be used in the embodiments of the present application will be briefly introduced below. The drawings described below are merely some embodiments of the present application, and it is obvious to those skilled in the art that other drawings can be derived from the drawings without creative effort. FIG. 1 is a schematic diagram of one embodiment of a battery cell of the present application. Figure 2 is an exploded schematic diagram of an embodiment of the battery cell of Figure 1. FIG. 3 is a schematic diagram of one embodiment of the battery module of the present application. FIG. 4 is a schematic diagram of one embodiment of the battery pack of the present application. Figure 5 is an exploded schematic diagram of an embodiment of the battery pack shown in Figure 4. FIG. 6 is a schematic diagram of one embodiment of an electric device including a battery cell of the present application as a power source. The drawing may not be drawn according to actual proportions. Specific details for implementing the invention

[0228] Hereinafter, embodiments specifically disclosed in the modified carboxymethylcellulose salt, cathode dispersant, cathode sheet, battery cell, battery, and electric device of the present application will be described in detail with appropriate reference to the drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of known matters and repetitive descriptions of structures that are actually identical may be omitted. This is intended to prevent the following description from becoming unnecessarily long and to enable those skilled in the art to easily understand it. Furthermore, the drawings and the following description are provided to enable those skilled in the art to fully understand the present application and are not intended to limit the subject matter described in the claims.

[0229] The “range” disclosed in this application is limited in the form of lower and upper limits, and a given range is limited by selecting one lower limit and one upper limit, and the selected lower limit and upper limit define the boundaries of a specific range. A range limited in this way may include or not include endpoint values ​​and may be arbitrarily combined, that is, any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60 to 120 and 80 to 110 are listed for a specific parameter, it is understood that ranges of 60 to 110 and 80 to 120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed and maximum range values ​​3, 4 and 5 are listed, ranges such as 1 to 3, 1 to 4, 1 to 5, 2 to 3, 2 to 4, and 2 to 5 may all be expected. In this application, unless otherwise stated, the numerical range “a to b” represents an abbreviated expression of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range “0 to 5” indicates that all real numbers between “0 to 5” are listed in this specification, and “0 to 5” is merely an abbreviated expression of a combination of such numbers. Additionally, if a parameter is represented as an integer ≥ 2, this corresponds to disclosing that the parameter is, for example, an integer 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0230] Unless otherwise specified, all embodiments of the present application and selectable embodiments may be combined with one another to form a new technical solution.

[0231] Unless otherwise specified, all technical features of the present application and selectable technical features may be combined with one another to form a new technical solution.

[0232] Unless otherwise specified, all steps of the present application may proceed sequentially or randomly, preferably sequentially. For example, that a method comprises steps a and b indicates that the method may comprise steps a and b performed sequentially, or steps b and a performed sequentially. For example, that a method may further comprise step c indicates that step c may be added to the method in any order, and, for example,

[0233] The method may include steps a, b, and c, or steps a, c, and b, or steps c, a, and b, etc.

[0234] Unless otherwise specified, "includes" and "comprehensively" as used in this application indicate an open or closed form. For example, "includes" and "comprehensively" may indicate that other unlisted components are additionally included or included, or that only the listed components are included or included.

[0235] Unless otherwise specified, the term “or” in this application has a comprehensive meaning. For example, the phrase “A or B” indicates “A, B, or both A and B.” More specifically, conditions where A is true or exists and B is false or does not exist; conditions where A is false or does not exist and B is true or exists; or conditions where both A and B are true or exist all satisfy the condition “A or B”.

[0236] In each part of this specification, substituents of compounds are disclosed as groups or ranges. It is clearly expected that these descriptions will include each individual sub-combination of the members of these groups and ranges. For example, it is clearly expected that the term "C1 to C8 alkyl group" will individually disclose C1, C2, C3, C4, C5, C6, C7, C8, C1 to C8, C1 to C7, C1 to C6, C1 to C5, C1 to C4, C1 to C3, C1 to C2, C2 to C8, C2 to C7, C2 to C6, C2 to C5, C2 to C4, C2 to C3, C3 to C8, C3 to C7, C3 to C6, C3 to C5, C3 to C4, C4 to C8, C4 to C7, C4 to C6, C4 to C5, C5 to C8, C5 to C7, C5 to C6, C6 to C8, C6 to C7 and C7 to C8 alkyl groups.

[0237] In another embodiment, it is clearly expected that integers of the range 5 to 40, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, and 40, will be disclosed individually; It is clearly expected that integers in the range 1 to 20 will individually disclose 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20. Based on this, other groups or ranges can be clearly expected.

[0238] The cathode sheet comprises a cathode current collector and a cathode film layer installed on at least one side of the cathode current collector, and the cathode film layer is formed by applying a cathode slurry to the cathode current collector and drying it. However, during the process of forming the cathode film layer with the cathode slurry, phenomena such as cracking may occur, which prevents the cathode sheet from meeting production requirements; and in order to improve the energy density of the battery cell, the cathode film layer is typically coated thickly, but this further exacerbates the cracking phenomenon of the cathode film layer, making it difficult to coat the cathode sheet thickly. In order to improve the cracking phenomenon of the cathode film layer, a plasticizer such as butanediol is added to the cathode slurry in the related technology. The plasticizer is typically a small molecule compound with a relatively small molecular weight, and it can enter between the binder polymer molecular chains and reduce the stress between binder polymer molecules, thereby lowering the crystallinity of the polymer molecular chains. Consequently, it improves the moldability and flexibility of the cathode film layer and improves the cracking phenomenon of the cathode film layer. However, the remaining plasticizer causes the thickness of the cathode film layer to become non-uniform, leading to interfacial problems such as black marks on the cathode film layer.

[0239] In light of the above-mentioned problem, the embodiments of the present application propose a modified carboxymethylcellulose salt, wherein the modified carboxymethylcellulose salt is obtained by opening a portion of the 6-membered ring of the carboxymethylcellulose salt, and after opening a portion of the 6-membered ring, the carbon chain segment length of the main chain of the modified carboxymethylcellulose salt increases, the rotationality of the main chain increases, and flexibility is improved, thereby improving the flexibility of the modified carboxymethylcellulose salt; when the modified carboxymethylcellulose salt is used as a component of a cathode dispersant, the flexibility of the cathode film layer can be effectively improved and the risk of cracking can be reduced, and furthermore, the modified carboxymethylcellulose salt can perform an excellent dispersion action on the cathode active material, etc., so that the cathode active material is effectively dispersed, so that the cathode active material is uniformly dispersed, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform.

[0240] Modified carboxymethylcellulose

[0241] In a first aspect, an embodiment of the present application proposes a modified carboxymethylcellulose salt, wherein the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A, and

[0242] Formula A,

[0243] In Equation A,

[0244] Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + It includes at least one of the following; for example, the metal ion includes at least one of lithium ions, sodium ions, and potassium ions;

[0245] R comprises a hydrogen atom or a flexible group, wherein the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group.

[0246] Carboxymethylcellulose salt (CMC-M) is a type of anionic water-soluble cellulose etherification derivative, and when applied to a cathode slurry, it can reduce the interfacial tension between the cathode active material and the solvent, thereby providing good dispersion for the cathode active material, and under stirring, the cathode active material is uniformly dispersed in the solvent, which is advantageous for forming a stable slurry system.

[0247] In one embodiment, the carboxymethylcellulose salt is connected by a six-membered heterocycle to form a molecular chain, and the six-membered heterocycle has relatively high rigidity and is difficult to rotate, so the carboxymethylcellulose salt has relatively high rigidity and low flexibility. In another embodiment, the molecular chain of the carboxymethylcellulose salt is rich in hydroxyl groups (-OH), and the hydroxyl groups allow relatively strong van der Waals forces or hydrogen bonds to be formed between the molecular chains of the carboxymethylcellulose salt itself, thereby causing the cathode slurry to have relatively strong drying stress during the drying process, resulting in warping, and cracking may occur during the additional rolling process, causing cracking phenomena in the cathode film layer.

[0248] The cathodic dispersant of an embodiment of the present application comprises a modified carboxymethylcellulose salt, wherein the modification of the carboxymethylcellulose salt is achieved by opening a portion of the ring structure of the carboxymethylcellulose salt (CMC-M) or by additionally grafting a flexible group after ring opening; after some six-membered rings are opened, the carbon chain segment length of the main chain of the modified carboxymethylcellulose salt increases, the rotationality of the main chain increases, and flexibility is improved;

[0249] Flexible groups can be additionally grafted at ring-opened positions, and these groups can reduce the interaction force between polymer molecular chains, thereby reducing the stress generated during the drying process; furthermore, since the flexible groups have a certain flexibility, the flexibility of the modified carboxymethylcellulose salt can be improved, and when a cathode dispersant is applied to the cathode slurry, the drying stress of the cathode slurry during the drying process becomes relatively small, thereby reducing the risk of cracking in the cathode film layer and improving the flexibility of the cathode film layer, particularly reducing the risk of cracking in a thickly coated cathode film layer, and is advantageous for improving the energy density of the battery cell.

[0250] Accordingly, when the modified carboxymethylcellulose salt is applied to the cathode slurry, the cathode film layer formed by drying the cathode slurry can achieve a thick coating, the performance of the cathode film layer is uniform, and the flexibility is relatively excellent.

[0251] In some embodiments, the cation of the modified carboxymethylcellulose salt is a metal ion or an ammonium ion (NH4 + It includes at least one of ). For example, the metal ion includes at least one of lithium ions, sodium ions, and potassium ions.

[0252] In some embodiments, the modified carboxymethylcellulose salt comprises at least one of the modified carboxymethylcellulose lithium salt, the modified carboxymethylcellulose sodium salt, or the modified carboxymethylcellulose ammonium salt. The above-described material has good dispersibility.

[0253] In some other embodiments, the modified carboxymethylcellulose salt may further include the modified carboxymethylcellulose potassium salt, etc.

[0254] In some embodiments, the modified carboxymethylcellulose salt further comprises a structural unit represented by Formula B, and

[0255] Formula B,

[0256] In Equation B,

[0257] M2 is metal ions or NH4 + It includes at least one of the following. For example, the metal ion includes at least one of lithium ions, sodium ions, and potassium ions.

[0258] The modified carboxymethylcellulose salt is modified by opening the ring and grafting based on the carboxymethylcellulose salt. The main chain structure of the modified carboxymethylcellulose salt is still based on the main chain structure of the carboxymethylcellulose salt, and the host structure of the modified carboxymethylcellulose salt is still the carboxymethylcellulose salt. Therefore, it still has a relatively excellent dispersion function, which can effectively reduce the interfacial tension between the cathode active material and the solvent, thereby uniformly dispersing the cathode active material in the cathode slurry. Additionally, the modified carboxymethylcellulose salt enables a uniform thickness distribution of the cathode film layer.

[0259] In some embodiments, Q includes a hydrogen atom, and the structural unit represented by Formula A includes the structural unit represented by Formula A-1.

[0260] Formula A-1

[0261] In some embodiments, the modified carboxymethylcellulose salt further comprises a structural unit represented by Formula C, and

[0262] Formula C,

[0263] In Equation C,

[0264] M3 is metal ions or NH4 + It includes at least one of the following. For example, the metal ion includes at least one of lithium ions, sodium ions, and potassium ions.

[0265] In some embodiments, Q includes -CH2COOM1, and the structural unit represented by Formula A includes the structural unit represented by Formula A-2.

[0266] Formula A-2

[0267] In some embodiments, the modified carboxymethylcellulose salt further comprises a structural unit represented by Formula D.

[0268] Formula D

[0269] In some embodiments, based on the total quantity of structural units represented by Formula A and structural units represented by Formula B, the quantity share of the structural unit represented by Formula A is 0.5% to 20%, optionally 1% to 10%.

[0270] For example, the quantity share of the structural unit represented by Equation A is 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, or is in a range consisting of any two values ​​mentioned above.

[0271] When the quantity share of the structural unit represented by Formula A is within the range described above, the modified carboxymethylcellulose salt has excellent hydrophobicity, so it can have excellent dispersion for a negative electrode active material such as graphite material and can effectively improve the flexibility of the carboxymethylcellulose salt.

[0272] The quantity of structural units can be calculated by detecting groups or elements unique to the structural units, and can be tested by at least one of the following methods: infrared spectroscopy (IR), nuclear magnetic resonance (NMR), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), titration, etc.

[0273] In an embodiment of the present application, detection is performed by infrared spectroscopy (IR); specifically, the polymer is tested using a Thermo Nicolet Nexus 670 attenuated total reflection Fourier transform infrared spectrometer (FTIR-ATR), and then tested according to the GB / T6040-2002 standard, with a test range of 600 to 4000 cm² using the ATR method. -1 ; Repeatability: ±2cm -1 ; Resolution: 4cm -1 The penetration depth is 0.2 to 0.6 μm.

[0274] In an embodiment of the present application, testing is performed using nuclear magnetic resonance (NMR), specifically, 1H NMR and 13C NMR are measured in a Varian Mercury Plus-400 nuclear magnetic resonance spectrometer, the test temperature is 20°C, the internal standard material is TMs, the solvent is CDCl3, and the proton resonance frequency is 400 MHz.

[0275] In an embodiment of the present application, the test is performed using pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), and the specific test steps are as follows. A sample of 0.5 mg is accurately weighed and placed in a sample cup, fixed to an injection rod, and then placed in a pyrolysis unit mounted near the GC gas chromatography injection port. When the temperature of the pyrolysis unit reaches a set temperature, the injection button is pressed, and the sample cup free-falls rapidly into the center of the pyrolysis unit. In an inert gas N2 atmosphere, the volatile components are vaporized instantaneously, separated by a carrier gas, and enter a gas chromatography column. Finally, the components are detected through a flame ionization detector (FID) or a mass spectrometer (MS) to obtain a gas chromatogram or a total ion chromatogram.

[0276] In an embodiment of the present application, the ring-opening quantity may be calculated through the content of characteristic groups, such as aldehyde groups, present in the intermediate generated during the manufacturing process of the modified carboxymethylcellulose salt, and specifically, it may be detected by titration.

[0277] [Flexible Group]

[0278] To further improve the flexibility of the cathodic dispersant, the flexible group is selected to have a long chain structure, for example, a long chain structure of C3 to C150. Since the long chain structure occupies a relatively long space, it has steric hindrance, which can further reduce the interaction force between molecular chains and further reduce drying stress, thereby reducing the risk of cracking in the cathodic film layer; the long chain structure also has excellent flexibility, which can improve the flexibility of the cathodic film layer and further reduce the risk of cracking in the cathodic film layer, thereby providing good flexibility when the cathodic dispersant is used as a cathodic slurry.

[0279] In some embodiments, the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group.

[0280] The aforementioned group is a long-chain group, thereby enabling the modified carboxymethylcellulose salt to have excellent flexibility, which can improve the flexibility of the cathode film layer formed by drying the cathode slurry.

[0281] When the above-described group is substituted by a substituent, the substituent may include a halogen atom or a heteroatom-containing group, the halogen atom may include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, etc., and the heteroatom may include a nitrogen atom, a sulfur atom, or an oxygen atom, etc.

[0282] [Ether Group]

[0283] In some embodiments, the flexible group comprises a substituted or unsubstituted ether group, optionally a substituted or unsubstituted C3 to C150 ether group. Since the ether group has a relatively long chain length, it can increase the flexibility of the flexible group, thereby increasing the flexibility of the modified carboxymethylcellulose salt.

[0284] In some embodiments, the ether group includes a structural formula represented by Formula 1, and

[0285] Equation 1,

[0286] In Equation 1,

[0287] R 11 to R 17 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkenyl group.

[0288] Optionally, when the above-described group is substituted, the substituent may include a halogen atom, wherein the halogen atom may include at least one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0289] m is the quantity of the repeating structure. m includes any positive integer from 5 to 60. Optionally, m includes any positive integer from 5 to 45. When m is within the range described above, a good dispersion effect can still be achieved on a basis that reduces the hydrogen bonding activity of the cathodic dispersant.

[0290] In some embodiments, m may be 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, or 60.

[0291] For example, the ether group includes at least one of the structural formulas represented by Formula 1-1 to Formula 1-14.

[0292] Equation 1-1, Equation 1-2,

[0293] Equation 1-3, Equation 1-4,

[0294] Equation 1-5,

[0295] Equation 1-6,

[0296] Equation 1-7, Equation 1-8,

[0297] Equation 1-9, Equation 1-10, Equation 1-11, Equation 1-12, Equation 1-13, Equation 1-14

[0298] In some embodiments, m1 is a quantity of repeating structures, and m1 includes any positive integer from 1 to 30, and may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0299] In an embodiment of the present application, m-m1 represents a value obtained by subtracting m1 from m, and m-m1 includes any positive integer from 1 to 30, and may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0300] [Substituted or unsubstituted alkyl group]

[0301] In some embodiments, the flexible group comprises a substituted or unsubstituted alkyl group, optionally a substituted or unsubstituted C3 to C150 alkyl group. The alkyl group may comprise an unsaturated alkyl group or a saturated alkyl group, and the unsaturated alkyl group may be an alkyl group having a ring structure, for example, a 3-membered ring, a 5-membered ring, etc. An alkyl group having a ring structure may further increase steric hindrance, thereby reducing drying stress. The saturated alkyl group may comprise a branched-chain alkyl group or a straight-chain alkyl group, and since the saturated alkyl group, particularly the straight-chain alkyl group, has a relatively long chain length, it can improve the flexibility of the modified carboxymethylcellulose salt.

[0302] In some embodiments, the substituted or unsubstituted C3 to C150 alkyl group comprises the structural formula represented by Formula 2, and

[0303] Equation 2,

[0304] In Equation 2,

[0305] R 21 to R 27 Each independently comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group.

[0306] Optionally, R 21 to R 27 Each independently comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 saturated alkyl group.

[0307] Optionally, when the above-described group is substituted, the substituent may include a halogen atom, wherein the halogen atom may include at least one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0308] s is the quantity of repeating structures, and s includes any positive integer from 5 to 60. Optionally, s includes any positive integer from 5 to 45. When s is within the range described above, a good dispersion effect can still be achieved on a basis that reduces the hydrogen bonding action of the cathodic dispersant.

[0309] In some embodiments, s may be 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, or 60.

[0310] For example, the substituted or unsubstituted C3 to C150 alkyl group comprises at least one of the structural formulas represented by Formula 2-1 to Formula 2-11.

[0311] Equation 2-1, Equation 2-2,

[0312] Equation 2-3, Equation 2-4,

[0313] Equation 2-5,

[0314] Equation 2-6, Equation 2-7,

[0315] Equation 2-8, Equation 2-9,

[0316] Equation 2-10, Equation 2-11

[0317] In some embodiments, s1 is a quantity of repeating structures, and s1 includes any positive integer from 1 to 30. s1 may be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0318] In an embodiment of the present application, s-s1 represents a value obtained by subtracting s1 from s, and s-s1 includes any positive integer from 1 to 30. It represents 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0319] [Substituted or unsubstituted polyolefin groups]

[0320] In some embodiments, the flexible group comprises a substituted or unsubstituted polyolefin group, optionally a substituted or unsubstituted C3 to C150 polyolefin group. Since the polyolefin group has a relatively long chain length, it can improve the flexibility of the modified carboxymethylcellulose salt.

[0321] In some embodiments, the substituted or unsubstituted C3 to C150 polyolefin group comprises the structural formula represented by Formula 3, and

[0322] Equation 3,

[0323] In Equation 3,

[0324] R 31 to R 34 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C2 to C10 alkenyl group;

[0325] R 35 It comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group.

[0326] Optionally, when the above-described group is substituted, the substituent may include a halogen atom, wherein the halogen atom may include at least one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0327] p is the quantity of the repeating structure, and p includes any positive integer from 5 to 60. Optionally, p includes any positive integer from 5 to 45. When p is within the range described above, good dispersion performance can be achieved on a basis that reduces the hydrogen bonding activity of the cathodic dispersant.

[0328] In some embodiments, p may be 5, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, or 60.

[0329] For example, substituted or unsubstituted C3 to C150 polyolefin groups include at least one of the structural formulas represented by Formula 3-1 to Formula 3-8.

[0330] Equation 3-1, Equation 3-2,

[0331] Equation 3-3, Equation 3-4,

[0332] Equation 3-5, Equation 3-6,

[0333] Equation 3-7, Equation 3-8

[0334] In each of the embodiments described above, the halogen atom may include at least one of a fluorine atom, a chlorine atom, and a bromine atom. The aforementioned atoms can also improve the withstand voltage of the cathodic dispersant, thereby improving the stability of the cathodic film layer.

[0335] [Substituted or unsubstituted amide groups]

[0336] In some embodiments, the flexible group comprises a substituted or unsubstituted amide group, and optionally a substituted or unsubstituted C3 to C150 amide group.

[0337] The amide group may include a monomeric amide group or a polyamide group, and the amide group contains a nitrogen element, which is an element with strong electronegativity. When the amide group is grafted onto the side chain of a carboxymethylcellulose salt, it can destroy the regular OHO hydrogen bond structure of the carboxymethylcellulose salt and form a new NHO hydrogen bond structure. Since the NHO hydrogen bond structure has weaker hydrogen bonding activity compared to OHO, it weakens the intermolecular forces of the graft-modified carboxymethylcellulose salt, thereby increasing flexibility and improving the flexibility of the cathode film layer. Additionally, the nitrogen element, which is an element with strong electronegativity, can form a complex with active ions in the battery system, such as lithium ions or sodium ions, thereby increasing the transport rate of active ions and improving the kinetic performance of the battery cell.

[0338] In some embodiments, the substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4, and

[0339] Equation 4,

[0340] In Equation 4,

[0341] R 41 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0342] R 42 to R 46 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0343] a is a quantity of the repeating structure, and a includes any positive integer from 1 to 30. a can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0344] Optionally, when the above-described group is substituted, the substituent may include at least one of a halogen atom, a hydroxyl group, and a carboxyl group, wherein the halogen atom may include at least one of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

[0345] Any of the two ends of the amide group of Formula 4 may be connected to an oxygen atom in the modified carboxymethylcellulose salt, for example, the left end group may be connected to an oxygen atom, or the right end group may be connected to an oxygen atom. The end group of the amide group of Formula 4 that is not connected to an oxygen atom may include a hydrogen atom or a C1 to C3 alkyl group.

[0346] In some embodiments, R 41 The C3 to C150 amide group comprises a single bond and has a substituted or unsubstituted structure formula represented by Formula 4-1.

[0347] Equation 4-1

[0348] For example, the structural formula represented by Formula 4-1 includes at least one of the structural formulas represented by Formula 4-11 to Formula 4-15.

[0349] Equation 4-11, Equation 4-12,

[0350] Equation 4-13, Equation 4-14,

[0351] Equation 4-15

[0352] In some embodiments, R 41 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4-2,

[0353] Equation 4-2,

[0354] a1 is a quantity of the repeating structure, and a1 includes any positive integer from 1 to 5. For example, a1 can be 1, 2, 3, 4, or 5.

[0355] In some embodiments, the structural formula represented by Formula 4-2 includes at least one of the structural formulas represented by Formula 4-21 to Formula 4-24.

[0356] Equation 4-21, Equation 4-22, Equation 4-23, Equation 4-24

[0357] [Substituted or unsubstituted ester groups]

[0358] In some embodiments, the flexible group comprises a substituted or unsubstituted ester group, and optionally a substituted or unsubstituted C3 to C150 ester group.

[0359] The ester group may include monomeric ester groups or polyester groups, and when the ester group is grafted onto the side chain of the carboxymethylcellulose salt, it can destroy the regular OHO hydrogen bond structure of the carboxymethylcellulose salt and weaken the hydrogen bonding action of the carboxymethylcellulose salt itself, thereby weakening the intermolecular forces of the graft-modified carboxymethylcellulose salt, increasing flexibility and improving the flexibility of the cathode film layer; and also improve the mobility of active ions such as lithium ions. In addition, the ester group has relatively good flexibility of its own and can further improve the flexibility of the carboxymethylcellulose salt after substitution at the hydroxyl group position, thereby improving the flexibility of the cathode film layer.

[0360] In some embodiments, the substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5, and

[0361] Equation 5,

[0362] In Equation 5,

[0363] R 51 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0364] R 52 It comprises substituted or unsubstituted C1 to C5 alkyl groups;

[0365] R 53 to R 55 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0366] b is a quantity of the repeating structure, and b includes any positive integer from 1 to 30. b can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, or 30.

[0367] Any of the two ends of the ester group of Formula 5 can be connected to an oxygen atom in the modified carboxymethylcellulose salt, for example, the left end group is connected to an oxygen atom, or the right end group is connected to an oxygen atom. The end group of the ester group of Formula 5 that is not connected to an oxygen atom may include a hydrogen atom or a C1 to C3 alkyl group.

[0368] In some embodiments, R 51 The C3 to C150 ester group, which includes a single bond, includes the structural formula represented by Formula 5-1, which is substituted or unsubstituted.

[0369] Equation 5-1

[0370] For example, the structural formula represented by Formula 5-1 includes at least one of the structural formulas represented by Formula 5-11 to Formula 5-16.

[0371] Equation 5-11, Equation 5-12, Equation 5-13, Equation 5-14, Equation 5-15, Equation 5-16

[0372] In some embodiments, R 51 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5-2,

[0373] Equation 5-2,

[0374] b1 is a quantity of the repeating structure, and b1 includes any positive integer from 1 to 5, for example, b1 can be 1, 2, 3, 4 or 5.

[0375] For example, the structural formula represented by Formula 5-2 includes at least one of the structural formulas represented by Formula 5-21 to Formula 5-28.

[0376] Equation 5-21, Equation 5-22, Equation 5-23, Equation 5-24,

[0377] Equation 5-25, Equation 5-26,

[0378] Equation 5-27, Equation 5-28

[0379] In each of the embodiments described above, the halogen atom may include at least one of a fluorine atom, a chlorine atom, and a bromine atom. The aforementioned atoms can improve the dielectric strength of the polymer.

[0380] For example, the substituted or unsubstituted C3 to C150 ester group includes at least one of the structural formulas represented by Formula 5-21 to Formula 5-28.

[0381] Equation 5-21, Equation 5-22, Equation 5-23, Equation 5-24,

[0382] Equation 5-25, Equation 5-26,

[0383] Equation 5-27, Equation 5-28

[0384] In each of the embodiments described above, the weight average molecular weight of the flexible group is 78 Da to 5000 Da. Since the molecular weight of the graft group in the cathodic dispersant is relatively small, it is possible to reduce the hydrogen bonding between the molecular chains of the cathodic dispersant while allowing the cathodic dispersant to have relatively good dispersibility.

[0385] For example, the weight average molecular weight of the flexible group is 78Da, 80Da, 85Da, 88Da, 90Da, 92Da, 95Da, 98Da, 100Da, 120Da, 150Da, 200Da, 250Da, 300Da, 350Da, 400Da, 450Da, 500Da, 550Da, 600Da, 650Da, 700Da, 750Da, 800Da, 850Da, 900Da, 950Da, 1000Da, 1050Da, 1100Da, 1150Da, 1200Da, 1250Da, 1300Da, 1350Da, 1400Da, 1450Da, 1500Da, 1550Da, 1600Da, 1650Da, 1700Da, 1750Da, 1800Da, 1850Da, 1900Da, 1950Da, 2000Da, 2050Da, 2100Da, 2150Da, 2200Da, 2250Da, 2300Da, 2350Da, 2400Da, 2450Da, 2500Da, 3000Da, 3100Da, 3200Da, 3300Da, 3400Da, 3500Da, It may be 3600Da, 3700Da, 3800Da, 3900Da, 4000Da, 4100Da, 4200Da, 4300Da, 4400Da, 4500Da, 4600Da, 4700Da, 4800Da, 4900Da, 5000Da, or may be in a range consisting of any two values ​​mentioned above.

[0386] In some embodiments, the weight average molecular weight of the modified carboxymethylcellulose salt is 40 wDa to 80 wDa. When the weight average molecular weight of the modified carboxymethylcellulose salt is within the range described above, the cathodic dispersant can be made to have excellent dispersion performance.

[0387] For example, the weight average molecular weight of the modified carboxymethylcellulose salt may be 40wDa, 42wDa, 45wDa, 46wDa, 48wDa, 50wDa, 52wDa, 55wDa, 58wDa, 60wDa, 62wDa, 65wDa, 68wDa, 70wDa, 72wDa, 75wDa, 78wDa, 80wDa, or may be in a range consisting of any two of the values ​​mentioned above.

[0388] In this application, the weight average molecular weight of the polymer can be tested by methods known in the art, for example, by gel permeation chromatography, for example by a Waters 2695 Isocratic HPLC-type gel permeation chromatography differential refraction detector 2141.

[0389] General sodium carboxymethylcellulose is a polymer in a solid state at room temperature. By dissolving sodium carboxymethylcellulose in water, which is a solvent, so that the mass content of sodium carboxymethylcellulose is 1%, stirring at 1200 rpm for 2 hours, placing it in an oven, and drying it at, for example, 40°C for 24 hours or more, a reference adhesive film can be obtained. The width of the reference adhesive film is 2.5 cm, the length is 5 cm, and the thickness is 1 mm; the elongation at break of the reference adhesive film is tested, and the elongation at break of the reference adhesive film is defined as 100%. It should be explained that general sodium carboxymethylcellulose refers to sodium carboxymethylcellulose in which the hydrogen atoms in the side chains, particularly at the hydroxyl group positions, are not substituted by other groups.

[0390] In some embodiments, a modified carboxymethylcellulose salt is prepared into an adhesive film by dissolving the modified carboxymethylcellulose salt in water, which is a solvent, so that the mass content of the modified carboxymethylcellulose salt is 1%, stirring at 1200 rpm for 2 hours, placing it in an oven, and drying it at, for example, 40°C for 24 hours or more, thereby obtaining an adhesive film, the width of the adhesive film is 2.5 cm, the length is 5 cm, and the thickness is 1 mm; and when the elongation at break of the adhesive film is tested and calculated based on the elongation at break of a reference adhesive film of 100%, the elongation at break of the adhesive film is 225% to 400%. When preparing the adhesive film, the thickness deviation of the adhesive film can be controlled within a range of 0.5%.

[0391] Accordingly, the elongation at break of the cathode dispersant is higher than that of general carboxymethylcellulose sodium, and when the cathode dispersant is applied to the cathode sheet, the flexibility becomes relatively excellent and it does not break easily.

[0392] For example, the breaking elongation of the adhesive film may be 225%, 230%, 240%, 250%, 260%, 270%, 280%, 290%, 300%, 320%, 350%, 380%, 400%, or may be in a range consisting of any two of the values ​​mentioned above.

[0393] In the present application, the elongation at break of the adhesive film has a meaning known in the art and can be tested using equipment and methods known in the art, specifically according to the GB / T36363-2018 standard.

[0394] Modified carboxymethylcellulose salts can be prepared by the following method.

[0395] In some embodiments, the method includes an epoxy ring-opening reaction treatment step S100.

[0396] In step S100, the epoxy ring-opening reaction treatment specifically includes the step of providing a carboxymethylcellulose salt, mixing a ring-opening agent and the carboxymethylcellulose salt, and then performing a ring-opening treatment so that the ring is opened at two adjacent hydroxyl group positions of the carboxymethylcellulose salt.

[0397] In some embodiments, the ring-opening agent comprises at least one of sodium tert-butoxide and potassium tert-butoxide.

[0398] In some other embodiments, the method includes an epoxy ring-opening reaction treatment step S100 and a substitution treatment step S200.

[0399] In step S100, the epoxy ring-opening reaction treatment specifically includes the step of providing a carboxymethylcellulose salt, mixing a ring-opening agent and the carboxymethylcellulose salt, and then performing a ring-opening treatment to cause ring opening at two adjacent hydroxyl group positions of the carboxymethylcellulose salt. Optionally, after the ring-opening treatment, an acidic catalyst is added to activate the hydroxyl group at the ring-opening position to an aldehyde group.

[0400] In some embodiments, the ring-opening agent comprises at least one of sodium tert-butoxide and potassium tert-butoxide.

[0401] In some embodiments, the acidic catalyst includes phosphoric acid, etc.

[0402] In step S200, the substitution treatment specifically includes the step of adding a substituent compound to the system to perform a substitution reaction, wherein the substituent compound is substituted at the aldehyde group position, and the substituted product is the modified carboxymethylcellulose salt. Optionally, after substitution, the aldehyde group is reduced to a hydroxyl group, and the reducing agent may include at least one of sodium borohydride or lithium aluminum hydride.

[0403] Substitutional compounds include flexible compounds.

[0404] In some embodiments, the substituted compound comprises substituted or unsubstituted ethers, optionally substituted or unsubstituted C3 to C150 ethers.

[0405] For example, substituted or unsubstituted C3 to C150 ethers include compounds represented by Formula 11, and

[0406] Equation 11,

[0407] In Equation 11,

[0408] R 11 to R 17 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkenyl group.

[0409] m includes any positive integer from 5 to 60.

[0410] In some embodiments, the substituted compound comprises a substituted or unsubstituted alkane, optionally a substituted or unsubstituted C3 to C150 alkane.

[0411] For example, substituted or unsubstituted C3 to C150 alkanes include compounds represented by Formula 21, and

[0412] Equation 21,

[0413] In Equation 21,

[0414] R 21 to R 27 Each independently comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0415] s includes any positive integer from 5 to 60.

[0416] In some embodiments, the substituted compound comprises a substituted or unsubstituted polyolefin, optionally a substituted or unsubstituted C3 to C150 polyolefin.

[0417] For example, substituted or unsubstituted C3 to C150 polyolefins comprise compounds represented by Formula 31, and

[0418] Equation 31,

[0419] In Equation 31,

[0420] R 31 to R 34 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C2 to C10 alkenyl group;

[0421] R 35 It comprises at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group;

[0422] p includes any positive integer from 5 to 60.

[0423] In some embodiments, the substituted compound comprises a substituted or unsubstituted amide compound, optionally a substituted or unsubstituted C3 to C150 amide compound, and may be a C3 to C150 amide polymer.

[0424] For example, substituted or unsubstituted C3 to C150 amide polymers include compounds represented by Formula 41, and

[0425] Equation 41,

[0426] In Equation 41,

[0427] R 41 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0428] R 42 to R 46Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0429] R 47 and R 48 Each independently contains a hydrogen atom or a C1 to C3 alkyl group.

[0430] a includes any positive integer from 1 to 30.

[0431] In some embodiments, the substituted compound comprises a substituted or unsubstituted ester compound, optionally a substituted or unsubstituted C3 to C150 ester compound, and optionally a C3 to C150 ester polymer.

[0432] For example, substituted or unsubstituted C3 to C150 ester polymers include compounds represented by Formula 51, and

[0433] Equation 51,

[0434] In Equation 51,

[0435] R 51 It comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group;

[0436] R 52 It comprises substituted or unsubstituted C1 to C5 alkyl groups;

[0437] R 53 to R 55 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group;

[0438] R 56 and R 57 Each independently comprises a hydrogen atom or a C1 to C3 alkyl group;

[0439] b includes any positive integer from 1 to 30.

[0440] In the preparation of modified carboxymethylcellulose salts, the reaction can be carried out under reaction conditions commonly used in the field, and the input ratio of each raw material can be selected according to the input ratios commonly used in the field. The ring opening rate of the modified carboxymethylcellulose salts can be calculated based on the input ratio.

[0441] cathodic dispersant

[0442] In a second aspect, an embodiment of the present application proposes a cathodic dispersant, wherein the cathodic dispersant comprises a modified carboxymethylcellulose salt according to any one embodiment of the first aspect of the present application.

[0443] In some embodiments, the cathodic dispersant may further include a carboxymethylcellulose salt.

[0444] In some embodiments, the ratio of the mass content of the carboxymethylcellulose salt to the mass content of the modified carboxymethylcellulose salt may be 0.5 to 2. When the sum of the ratios of the mass content of the carboxymethylcellulose salt and the modified carboxymethylcellulose salt is within the range described above, it can work together with the modified carboxymethylcellulose salt to improve the flexibility of the self-formed adhesive film and reduce the risk of cracking in the cathode film layer.

[0445] For example, the ratio of the mass content of the carboxymethylcellulose salt to the mass content of the modified carboxymethylcellulose salt may be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or may be in a range consisting of any two values ​​mentioned above.

[0446] cathode sheet

[0447] In a third aspect, an embodiment of the present application proposes a cathode sheet, wherein the cathode sheet comprises a cathode current collector and a cathode film layer installed on at least one surface of the cathode current collector, and the cathode film layer comprises a cathode dispersant according to any one embodiment of the second aspect of the present application. The cathode dispersant can be used as a dispersant for the cathode film layer, which allows the cathode active material to be uniformly dispersed in the cathode film layer, thereby making the performance of the cathode film layer uniform, and the dispersant can also improve the flexibility of the cathode film layer, thereby reducing the risk of cracking in the cathode film layer.

[0448] For example, the cathode current collector has two opposing surfaces in its thickness direction, and the cathode film layer is installed on one or both of the two opposing surfaces of the cathode current collector.

[0449] In some embodiments, based on the total mass of the cathode film layer, the mass content of the modified carboxymethylcellulose salt is 0.8% to 1.3%, optionally 1.0% to 1.3%, and more optionally 1.0% to 1.2%. When the mass content of the modified carboxymethylcellulose salt is within the above-described range, the risk of cracking in the cathode film layer can be effectively reduced, and the performance uniformity and flexibility of the cathode film layer can be effectively improved. Furthermore, since the occupancy rate is relatively low, it has almost no effect on the occupancy rate of the cathode active material, thereby allowing the battery cell to have a relatively high energy density. In addition, since the modified carboxymethylcellulose salt can significantly improve the flexibility of the cathode film layer, it is not necessary to add auxiliary agents such as plasticizers to the cathode slurry, and accordingly, the adverse effects caused by the introduction of plasticizers can be reduced.

[0450] For example, the mass content of the modified carboxymethylcellulose salt may be 0.80%, 0.85%, 0.90%, 0.95%, 1.00%, 1.01%, 1.02%, 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, 1.09%, 1.10%, 1.11%, 1.12%, 1.13%, 1.14%, 1.15%, 1.16%, 1.17%, 1.18%, 1.19%, 1.2%, 1.3%, or may be in a range consisting of any two of the values ​​mentioned above.

[0451] In some embodiments, the cathodic dispersant of the cathodic film layer may further include a carboxymethylcellulose salt such as at least one of sodium carboxymethylcellulose, potassium carboxymethylcellulose, lithium carboxymethylcellulose, etc., and the distinguishing feature between such a carboxymethylcellulose salt and the modified carboxymethylcellulose salt described above is as follows: the hydroxyl group in such a carboxymethylcellulose salt is not substituted, and the carboxymethylcellulose salt can exert a dispersion action together with the modified carboxymethylcellulose salt described above, and based on this, the modified carboxymethylcellulose salt can also further improve the flexibility of the cathodic film layer.

[0452] In some embodiments, based on the total mass of the cathode film layer, the mass content of the carboxymethylcellulose salt may be 0.05% to 1.0%; optionally, 0.05% to 0.3%. When the mass content of the carboxymethylcellulose salt is within the range described above, it can work together with the modified carboxymethylcellulose salt to improve the performance uniformity and flexibility of the cathode film layer.

[0453] For example, the mass content of carboxymethylcellulose salt is 0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.3%, 0.35%, 0.4%, 0.42%, 0.45%, 0.46%, 0.48%, 0.50%, 0.52%, 0.55%, 0.56%, 0.58%, 0.60%, 0.62%, 0.65%, 0.66%, 0.68%, 0.70%, 0.72%, 0.75%, 0.78%, 0.80%, 0.82%, 0.85%, 0.86%, 0.88%, 0.9%, 0.91%, It may be 0.92%, 0.93%, 0.94%, 0.95%, 0.96%, 0.97%, 0.98%, 0.99%, 1.00%, or may be in a range consisting of any two values ​​mentioned above.

[0454] In some embodiments, the ratio of the mass content of the carboxymethylcellulose salt to the mass content of the modified carboxymethylcellulose salt may be 0.5 to 2. When the sum of the ratios of the mass content of the carboxymethylcellulose salt and the modified carboxymethylcellulose salt is within the range described above, it can work together with the modified carboxymethylcellulose salt to improve the performance uniformity and flexibility of the cathode film layer.

[0455] For example, the ratio of the mass content of the carboxymethylcellulose salt to the mass content of the modified carboxymethylcellulose salt may be 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, or may be in a range consisting of any two values ​​mentioned above.

[0456] In some embodiments, the coating basis weight of the cathode film layer is 200 mg / 1540.25 mm 2 Up to 280 mg / 1540.25 mm 2 ; Optionally 220mg / 1540.25mm 2 Up to 280 mg / 1540.25 mm 2 It is. Since the coating basis weight of the cathode film layer is relatively high, it is advantageous for implementing a thick coating.

[0457] For example, the coating basis weight of the cathode film layer is 200 mg / 1540.25 mm 2 , 210mg / 1540.25mm 2 , 220mg / 1540.25mm 2 , 230mg / 1540.25mm 2 , 240mg / 1540.25mm 2 , 250mg / 1540.25mm 2 , 260mg / 1540.25mm 2 , 270mg / 1540.25mm 2 , 280mg / 1540.25mm 2 It may be either or, or be within a range consisting of any two values ​​mentioned above.

[0458] The negative electrode active material may adopt a negative electrode active material for a battery cell known in the art. As an example, the negative electrode active material may include, but is not limited to, at least one of natural graphite, artificial graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate. Silicon-based materials may include at least one of silicon element, silicon oxide, silicon-carbon composites, silicon nitrogen composites, and silicon alloy materials. Tin-based materials may include at least one of tin element, tin oxide, and tin alloy materials.

[0459] In some embodiments, the cathode active material may include at least one of natural graphite and artificial graphite, but is not limited thereto, and the cathode dispersant can effectively disperse the cathode active material described above to improve the dispersion uniformity of the cathode active material in the cathode film layer.

[0460] In some embodiments, the cathode film layer optionally further comprises a cathode conductive agent. The embodiments of the present application do not particularly limit the type of cathode conductive agent, and as an example, the cathode conductive agent may comprise at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0461] In some embodiments, the cathode film layer optionally further comprises a cathode binder. The embodiments of the present application do not particularly limit the type of cathode binder, and as an example, the cathode binder may comprise at least one of styrene-butadiene rubber (SBR), water-soluble unsaturated resin (SR-1B), water-soluble acrylic resin, for example, polyacrylic acid (PAA), polymethacrylic acid (PMAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl chitosan (CMCS). In some embodiments, the mass percentage content of the cathode binder is ≤5% based on the total weight of the cathode film layer.

[0462] In some embodiments, the cathode film layer optionally further comprises other auxiliary agents. As an example, the other auxiliary agent may include a thickener such as a PTC thermistor material. In some embodiments, the mass percentage content of the other auxiliary agent is ≤2% based on the total weight of the cathode film layer.

[0463] In some embodiments, the negative current collector may adopt a metal foil or a composite current collector. Copper foil may be adopted as an example of the metal foil. The composite current collector may include a polymer material base layer and a metal material layer formed on at least one surface of the polymer material base layer. As an example, the metal material may include at least one of copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy. As an example, the polymer material base layer may include at least one of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), and polyethylene (PE).

[0464] The cathode film layer is typically formed by coating a cathode slurry onto a cathode current collector, followed by drying and cold rolling. The cathode slurry is typically formed by dispersing a cathode active material, a cathode dispersant, an optional conductive agent, an optional binder, and other optional auxiliary agents in a solvent and stirring uniformly. The solvent may be N-methylpyrrolidone (NMP) or deionized water, but is not limited thereto.

[0465] The cathode sheet does not exclude additional functional layers other than the cathode film layer. For example, in some embodiments, the cathode sheet of the embodiment of the present application further comprises a conductive undercoating layer (e.g., composed of a conductive agent and a binder) interposed between the cathode current collector and the cathode film layer and installed on the surface of the cathode current collector. In other embodiments, the cathode sheet of the embodiment of the present application further comprises a protective layer coated on the surface of the cathode film layer.

[0466] battery cell

[0467] In a fourth aspect, an embodiment of the present application proposes a battery cell, and the battery cell includes a negative electrode sheet. The negative electrode sheet includes a negative electrode sheet according to any one embodiment of the third aspect of the present application. By adopting the said negative electrode sheet, the thickness of the negative electrode sheet becomes uniform, the performance becomes uniform, and it is advantageous to achieve uniform charging and discharging for each part of the negative electrode sheet during the cyclic charging and discharging process of the battery cell.

[0468] [Positive Sheet]

[0469] In some embodiments, the battery cell further includes a positive sheet.

[0470] The positive sheet comprises a positive current collector and a positive film layer installed on at least one surface of the positive current collector, and the positive film layer comprises a positive active material.

[0471] As an example, the positive current collector has two opposing surfaces in its own thickness direction, and the positive film layer is on one or both of the two opposing surfaces of the positive current collector.

[0472] In some embodiments, the positive current collector may adopt a metal foil or a composite current collector. For example, aluminum foil may be adopted as the metal foil. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material, such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, on a polymer material substrate such as polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.

[0473] In some embodiments, the positive electrode active material may include at least one of a lithium-containing transition metal oxide, a lithium-containing phosphate, and a modified compound thereof, but is not limited thereto. Examples of lithium transition metal oxides may include at least one of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, and a modified compound thereof, but are not limited thereto. Examples of lithium-containing phosphates may include at least one of lithium iron phosphate, a composite material of lithium iron phosphate and carbon, lithium manganese phosphate, a composite material of lithium manganese phosphate and carbon, lithium manganese iron phosphate, a composite material of lithium manganese iron phosphate and carbon, and a modified compound thereof, but are not limited thereto.

[0474] The positive film layer comprises a positive active material, and the positive active material may be a positive active material for a battery cell known in the art. As an example, the positive active material may include at least one of: a positive active material having a layered structure such as a ternary system, lithium / sodium nickel oxide, lithium / sodium cobalt oxide, lithium / sodium manganese oxide, a lithium / sodium-rich layered structure, and a rock salt-like layered structure; an olivine-type phosphate active material; and a positive active material having a spinel structure such as spinel lithium manganese oxide, spinel lithium nickel manganese oxide, lithium-rich spinel lithium manganese oxide, and lithium nickel manganese oxide.

[0475] For example, the general formula of a layered cathode active material is Li x A y Ni a Co b Mn c M 1-a-b-c Y zAnd, where, 0≤x≤2.1, 0≤y≤2.1 and 0.9≤x+y≤2.1; 0≤a≤1, 0≤b≤1, 0≤c≤1 and 0.1≤a+b+c≤1; 1.8≤z≤3.5; A is selected from one or more of Na, K, and Mg; M is selected from one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; and Y is selected from one or more of O and F. Optionally, y=0. Specifically, the layered cathode active material is lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium manganese oxide (LMO), and LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (NCM333), LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811) and LiNi 0.5 Co 0.2 Mn 0.3 It may include one or more of O2 (NCM523).

[0476] For example, the general formula of an olivine-type phosphate active material is Li x A y Me a M b P 1-c X c Y zAnd, where, 0≤x≤1.3, 0≤y≤1.3 and 0.9≤x+y≤1.3; 0.9≤a≤1.5, 0≤b≤0.5 and 0.9≤a+b≤1.5; 0≤c≤0.5; 3≤z≤5; A is selected from one or more of Na, K, and Mg; Me is selected from one or more of Mn, Fe, Co, and Ni; M is selected from one or more of B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; X is selected from one or more of S, Si, Cl, B, C, and N; and Y is selected from one or more of O and F. Specifically, the olivine-type phosphate active material includes one or more of LiFePO4, LiMnPO4, LiNiPO4, and LiCoPO4.

[0477] For example, the general formula of a spinel-structured cathode active material is Li x A y Mn a M 2-a Y z And, where, 0≤x≤2, 0≤y≤1, 0.9≤x+y≤2; 0.5≤a≤2; 3≤z≤5; A is selected from one or more of Na, K, and Mg; M is selected from one or more of Ni, Co, B, Mg, Al, Si, P, S, Ca, Sc, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Te, Ba, Ta, W, Yb, La, and Ce; and Y is selected from one or more of O and F. Specifically, the anode active material of the spinel structure is LiMn2O4, LiNi 0.5 Mn 1.5 O4, LiCr 0.3 Mn 1.7 O4, Li 1.1 Al 0.1 Mn 1.9 O4, Li2Mn2O4 and Li 1.5 It contains one or more of Mn2O4.

[0478] In the present application, the modified compound of each of the above-described positive electrode active materials may be a doping modified and / or surface coating modified for the positive electrode active material.

[0479] In some embodiments, the anode film layer optionally further comprises a binder. As an example, the binder may comprise at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorine-containing acrylate resin. In some embodiments, the mass percentage content of the binder is ≤5% based on the total weight of the anode film layer.

[0480] In some embodiments, the anode film layer optionally further comprises a conductive agent. As an example, the conductive agent may comprise at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers. In some embodiments, the mass percentage content of the conductive agent is ≤5% based on the total weight of the anode film layer.

[0481] In some embodiments, the anode sheet may be manufactured in the following manner: the above-described components used in the manufacture of the anode sheet, such as an anode active material, an optional conductive agent, an optional binder, and any other components, are dispersed in a solvent such as N-methylpyrrolidone to form an anode slurry; the anode slurry is coated onto an anode current collector, and the anode sheet is obtained through processes such as drying and cold rolling.

[0482] [Electrolyte]

[0483] In some embodiments, the battery cell further includes an electrolyte.

[0484] During the charging and discharging process of the battery cell, active ions move back and forth between the positive and negative sheets, being inserted and extracted, and the electrolyte acts to transfer active ions between the positive and negative sheets. In this application, the type of electrolyte is not specifically limited and can be selected according to actual requirements.

[0485] The electrolyte comprises an electrolyte salt and a solvent. The types of the electrolyte salt and solvent are not specifically limited and can be selected according to actual requirements.

[0486] As an example, the electrolyte salt may include, but is not limited to, at least one of lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), lithium perchlorate (LiClO4), lithium hexafluoroarsenate (LiAsF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(oxalato)borate (LiBOB), lithium difluorophosphate (LiPO2F2), lithium difluorobis(oxalato)phosphate (LiDFOP), and lithium tetrafluoro(oxalato)phosphate (LiTFOP).

[0487] As an example, the solvent may include, but is not limited to, at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), fluoroethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0488] In some embodiments, the electrolyte optionally further comprises additives. For example, the additives may include additives that can improve some performance of the battery, such as additives that form a positive film, additives that improve the overcharge performance of the battery, additives that improve the high-temperature performance of the battery, additives that improve the low-temperature power performance of the battery, etc.

[0489] [Separator]

[0490] In some embodiments, the battery cell further includes a separator.

[0491] In this application, the type of separation membrane is not specifically limited, and any known separation membrane with good chemical stability and mechanical stability may be selected.

[0492] In some embodiments, the material of the separator may include at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator may be a single-layer film or a multilayer composite film, and is not particularly limited. If the separator is a multilayer composite film, the material of each layer may be the same or different, and is not particularly limited.

[0493] In some embodiments, the anode sheet, separator, and cathode sheet may be manufactured into an electrode assembly through a winding process and / or a lamination process.

[0494] In some embodiments, the battery cell may include an external packaging material. The external packaging material may be used to package the electrode assembly and electrolyte described above.

[0495] In some embodiments, the external packaging material of the battery cell may be a rigid case, such as a rigid plastic case, an aluminum case, a steel case, etc. The external packaging material of the battery cell may also be a soft pack, such as an envelope-type soft pack. The material of the soft pack may be plastic, for example, at least one of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0496] In this application, the shape of the battery cell is not specifically limited and may be cylindrical, rectangular, or any other shape. FIG. 1 illustrates a battery cell (5) with a rectangular structure as an example.

[0497] In some embodiments, as illustrated in FIG. 2, the outer packaging material may include a case (51) and a cover plate (53). The case (51) may include a bottom plate and a side plate connected to the bottom plate, and the bottom plate and the side plate surround to form a receiving cavity. The case (51) has an opening communicating with the receiving cavity, and the cover plate (53) is installed over the opening to seal the receiving cavity. The positive electrode sheet, the negative electrode sheet, and the separator may undergo a winding process and / or a lamination process to form an electrode assembly (52). The electrode assembly (52) is packaged within the receiving cavity. The electrolyte is infiltrated into the electrode assembly (52). The number of electrode assemblies (52) included in the battery cell (5) may be one or more and may be adjusted as needed.

[0498] The method for manufacturing the battery cell of the present application is known. In some embodiments, a battery cell may be formed by assembling a positive electrode sheet, a separator, a negative electrode sheet, and an electrolyte. As an example, the positive electrode sheet, the separator, and the negative electrode sheet may be formed into an electrode assembly through a winding process and / or a lamination process, the electrode assembly may be placed in an outer packaging material and dried, then an electrolyte may be injected, and a battery cell may be obtained through processes such as vacuum packaging, settling, formation, and molding.

[0499] In some embodiments of the present application, the battery cell according to the present application may be assembled into a battery module, and the number of battery cells included in the battery module may be multiple, and the specific number may be adjusted according to the use and capacity of the battery module.

[0500] FIG. 3 is a schematic diagram of a battery module (4) as an example. As shown in FIG. 3, a plurality of battery cells (5) in the battery module (4) may be installed by being arranged sequentially along the length direction of the battery module (4). Of course, they may also be arranged in any other arbitrary way. Additionally, the plurality of battery cells (5) may be secured by fastening members.

[0501] Optionally, the battery module (4) may further include an outer case having a receiving space, and a plurality of battery cells (5) are received in the receiving space.

[0502] In some embodiments, the above-described battery module may be assembled into a battery pack, and the number of battery modules included in the battery pack may be adjusted according to the use and capacity of the battery pack.

[0503] FIGS. 4 and 5 are schematic diagrams of a battery pack (1) as an example. As shown in FIGS. 4 and 5, the battery pack (1) may include a battery box and a plurality of battery modules (4) installed within the battery box. The battery box includes an upper box (2) and a lower box (3), and the upper box (2) is covered by the lower box (3) to form a sealed space for accommodating the battery modules (4). The plurality of battery modules (4) may be arranged within the battery box in any manner.

[0504] The battery of the embodiment of the present application may include one battery cell or a plurality of battery cells, and when the battery includes a plurality of battery cells, the battery may include a battery module or a battery pack.

[0505] electrical device

[0506] In a fifth aspect, an embodiment of the present application provides an electric device, the electric device comprising at least one of a battery cell, a battery module, or a battery pack of the present application. The battery cell, battery module, or battery pack may be used as a power source for the electric device or as an energy storage unit for the electric device. The electric device may be, but is not limited to, mobile devices such as mobile phones and laptop computers, electric vehicles such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, electric trains, ships and satellites, energy storage systems, etc.

[0507] The electrical device can select a battery cell, battery module, or battery pack depending on usage requirements.

[0508] FIG. 6 is a schematic diagram of an electric device (6) as an example. The electric device (6) is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle. To meet the requirements of the electric device (6) for high power and high energy density, a battery pack (1) or a battery module may be adopted.

[0509] Other examples of electrical devices include mobile phones, tablet computers, and laptop computers. Such devices typically require lightweight design and may utilize battery cells as a power source.

[0510] Examples

[0511] The following embodiments provide a more detailed explanation of the contents disclosed in this application, but are for descriptive purposes only, as various modifications and changes made within the scope of the contents disclosed in this application are obvious to those skilled in the art. Unless otherwise specified, all parts, percentages, and ratios reported in the embodiments below are based on mass, all reagents used in the embodiments are commercially available or can be synthesized by general methods and can be used directly without further processing, and all apparatus used in the embodiments is commercially available.

[0512] Example 1 Manufacturing of a lithium-ion battery

[0513] 1. Manufacture of anode sheets

[0514] Aluminum foil was adopted as the positive current collector.

[0515] A positive electrode active material, lithium cobalt oxide (LiCoO2), a conductive agent, acetylene black, and a binder, polyvinylidene fluoride (PVDF), were uniformly mixed in a mass ratio of 95:2:3 in an appropriate amount of solvent, N-methylpyrrolidone (NMP), to obtain a positive electrode slurry; the positive electrode slurry was coated onto an aluminum foil, which is a positive electrode current collector, and then subjected to processes such as drying, cold rolling, slitting, and cutting to obtain a positive electrode sheet.

[0516] 2. Manufacture of cathode sheet

[0517] Copper foil was adopted as the cathode current collector.

[0518] A cathode slurry was prepared by uniformly mixing artificial graphite as a cathode active material, conductive carbon as a conductive agent, styrene acrylic emulsion as a binder, and a cathode dispersant in deionized water. The mass ratio of artificial graphite, conductive carbon as a conductive agent, styrene acrylic emulsion as a binder, and cathode dispersant in the solid content of the cathode slurry was 96.7:0.7:1.5:1.1, and the cathode dispersant contained modified CMC-Na. The cathode slurry was coated onto a copper foil as a current collector, dried at 85°C, and cold-rolled to obtain a cathode sheet having a cathode active material layer.

[0519] 3. Preparation of Electrolyte

[0520] In an environment with a moisture content of less than 10 ppm, an electrolyte solvent was obtained by mixing organic solvents ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and then lithium hexafluorophosphate, a lithium salt, was mixed with the solvent, and the lithium salt was 1 mol / L.

[0521] 4. Manufacture of lithium-ion batteries

[0522] An electrode assembly is obtained by sequentially stacking and winding an anode sheet, a polyethylene (PE) separator, and a cathode sheet; the electrode assembly is placed in an outer packaging material, dried, and then an electrolyte is injected, followed by processes such as vacuum packaging, settling, formation, and molding to obtain a lithium-ion battery.

[0523] Examples 2-1 to 2-5

[0524] The difference from Example 1 is that the type of flexible group of the cathodic dispersant in the cathodic slurry is different, and in Examples 2-5, only ring opening occurs, and flexible groups are not grafted after ring opening.

[0525] Example 3

[0526] The difference from Example 1 is that the quantity of the repeating structure of the flexible group of the cathode dispersant in the cathode slurry is different, and the input ratio is different.

[0527] Comparative Example 1

[0528] The difference from Example 1 is that the cathode dispersant added to the cathode slurry is replaced with sodium carboxymethylcellulose (CMC-Na), and the mass ratio of artificial graphite, conductive carbon as a conductive agent, styrene acrylic emulsion as a binder, and CMC-Na as a cathode dispersant in the solid content of the cathode slurry is 96.7:0.7:1.5:1.1.

[0529] Comparative Example 2

[0530] The difference from Example 1 is that the cathode dispersant added to the cathode slurry is replaced with sodium carboxymethylcellulose, a plasticizer is added to the cathode slurry, and the mass ratio of artificial graphite, conductive carbon as a conductive agent, styrene acrylic emulsion as a binder, CMC-Na as a cathode dispersant, and butanediol as a plasticizer in the solid content of the cathode slurry is 96.55:0.7:1.5:1.1:0.15.

[0531] The relevant parameters of the examples and comparative examples are as shown in Table 1.

[0532] Test section

[0533] 1. Cathode slurry filtration test

[0534] A 150 mesh filter screen was adopted, and the filter screen was cut with scissors to a size of 25cm x 25cm.

[0535] A 150 mesh filter screen was folded into a fan shape and suspended above the mouth of a clean beaker. 500 mL of cathode slurry was taken and poured onto the filter screen all at once, and the time was recorded from the moment the cathode slurry began to flow out from the end of the filter screen. The time taken to filter 300 mL was recorded.

[0536] 2. Gelation and sedimentation state of cathode slurry:

[0537] 500 ml of cathode slurry was taken and left for different periods of time to observe whether a gel-like state appeared in the cathode slurry, and the slurry viscosity was tested. As a result of the test, it is explained that slurry sedimentation occurred when the viscosity of the upper layer of the slurry in the beaker decreased and the lower layer of the slurry became thick.

[0538] 3. Coating basis weight of the cathode film layer

[0539] The coating window indicates the approximate critical range of the quality stability of the coated product, and if this range is exceeded, defects such as cracks occur. An extrusion coating machine was adopted to perform coating at a speed of 50 m / min, and as the coating mass of the cathode sheets of the comparative example and the example gradually increased, the occurrence of cracks in the film layer was observed. If no cracks occurred, weight was continued to be applied until cracks occurred in the film layer on the surface of the electrode sheet, and the coating weight that the cathode film layer could withstand without cracking was recorded, which is the coating basis weight of the cathode film layer in Table 1.

[0540] Test results

[0541] The test results are as shown in Table 1.

[0542] item cathode film layer Breaking elongation of cathodic dispersant / % cathodic dispersant Slurry filtration time / s@300mL Coating basis weight / mg / 1540.25mm 2 Flexible group Formula A, type Quantity of repeating structures Input ratio of flexible compound and CMC-M / 100 Quantity share % Example 1 Equation 1-1 35 1 1 75 220 225 Example 2-1 Equation 2-1 35 1 3 70 240 265 Example 2-2 Equation 3-7 35 3 3 76 250 281 Example 2-3 Equation 4-11 35 1 5 58 260 300 Example 2-4 Equation 5-11 5 1 10 60 280 340 Example 2-5 / / 0 5 75 260 296 Example 3 Equation 1-1 60 2 3 70 250 280 Comparative Example 1 CMC-Na doesn't exist doesn't exist doesn't exist 70 100 100 Comparative Example 2 CMC-Na doesn't exist doesn't exist doesn't exist 85 200 150

[0543] The weight average molecular weight of the cathodic dispersant in the examples and comparative examples is 60 wDa.

[0544] The quantity of repeating structures within a flexible group refers to the quantity of structures that are repeated continuously in the flexible group, for example, the value of m in Equation 1-1, the value of s in Equation 2-1, the value of p in Equation 3-7, the value of a in Equation 4-11, and the value of b in Equation 5-11.

[0545] The input ratio of flexible compound and carboxymethylcellulose salt (CMC-M) can be used to characterize the quantity share of flexible groups grafted onto the side chain after ring opening; specifically, it refers to the ratio of the mass of flexible compound and the mass of carboxymethylcellulose salt (CMC-M) in the raw material for producing modified CMC-M, and is calculated based on 100g of carboxymethylcellulose salt.

[0546] The quantity share of Equation A in Table 1 refers to the sum of the quantity shares of the structural unit represented by Equation A-1 and the structural unit represented by Equation A-2.

[0547] Each of the above-described examples and comparative examples showed that, as a result of gelation and sedimentation tests, no sedimentation or gelation occurred in the cathode slurry, and the state of the cathode slurry was relatively stable.

[0548] As can be seen from Table 1, Comparative Example 1 has sodium carboxymethylcellulose (CMC-Na), a dispersant, added to the cathode slurry, and the sodium carboxymethylcellulose has not undergone side chain modification. While this is advantageous for improving the dispersion performance of the cathode active material in the cathode slurry, due to the hydrogen bonding action present in sodium carboxymethylcellulose itself, the interaction between molecular chains becomes relatively strong, the drying stress during the drying process becomes relatively large, and the brittleness becomes relatively strong, making it easy for cracks to occur in the cathode film layer, which is disadvantageous for thick coating of the cathode slurry, and the coating basis weight is relatively small.

[0549] Compared to Comparative Example 1, Comparative Example 2 has more plasticizer added to the cathode slurry, and the plasticizer can effectively improve the moldability and flexibility of the cathode film layer, which is advantageous for thick coating of the cathode slurry, improves coating basis weight, and can improve cracking phenomena in the cathode film layer; however, as a result of the test, the cathode film layer with added plasticizer has non-uniform thickness, and thus the performance of the cathode film layer becomes non-uniform.

[0550] In the embodiments of the present application, no plasticizer is added to the cathode slurry, and sodium carboxymethylcellulose, which is a cathode dispersant, is partially ring-opened and can be further modified through side chain grafting, thereby reducing the hydrogen bonding action of the dispersant, weakening the interaction between the molecular chains of the dispersant, and improving the flexibility of the cathode dispersant. This improves the flexibility of the cathode film layer, thereby reducing the risk of cracking in the cathode film layer, and particularly reducing the risk of cracking in a thickly coated cathode film layer, thereby improving the energy density of the battery cell; furthermore, since the modified carboxymethylcellulose salt has relatively excellent dispersion and smoothing effects, it effectively disperses the cathode active material, allowing the cathode active material to be uniformly dispersed, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform.

[0551] By adjusting the opening rate of the embodiment of the present application so that the quantity share of the structural unit represented by Formula A is 0.5% to 20%, optionally 1% to 10%, the flexibility of the cathode film layer can be effectively improved, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform.

[0552] In the embodiments of the present application, when graft modification is performed on the side chain, at least one of an ether group, an alkyl group, an alkenyl group, an amide group, or an ester group may be adopted to perform the graft modification, and all of these can effectively improve the flexibility of the modified carboxymethylcellulose salt and improve the flexibility of the cathode film layer, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform.

[0553] In addition, if the number of repetitions of the structural units of the flexible group is adjusted to, for example, 1 to 60, the flexibility of the cathode film layer can still be improved, thereby making the thickness distribution of the cathode film layer uniform and making the performance uniform.

[0554] In the embodiments of the present application, the amount of dispersant added to the cathode slurry is adjusted and controlled to effectively control the thickness of the coating of the cathode slurry and improve the flexibility of the cathode film layer.

[0555] The present application detected the cathode sheet of Example 1 at several locations and, for example, performed ion milling cross-sectional elemental analysis (CP) at 10 locations of the cathode sheet in reference to GB / T 17359-2012 to confirm the thickness of the cathode film layer of the cathode sheet. If the thickness deviation of the cathode film layer measured at 10 locations is controlled within the range of 0.5%, the thickness of the cathode film layer of the cathode sheet can be considered to be uniform and the thickness consistency relatively high.

[0556] In this application, ten lithium-ion batteries were manufactured using the method of Example 1, and the average thickness of the negative film layer was measured for each lithium-ion battery. Specifically, ion milling cross-sectional elemental analysis (CP) was performed in reference to GB / T 17359-2012 to measure the thickness of the negative film layer at ten locations on the negative sheet, and the average value was calculated and used as the average thickness of the lithium-ion battery. The thickness variation of the negative film layer of the ten lithium-ion batteries was controlled within a range of 0.5%.

[0557] Even though illustrative embodiments have been shown and described, those skilled in the art should understand that the embodiments described above should not be interpreted as a limitation to the present application, and that changes, substitutions, and modifications to the embodiments may be made outside the spirit, principles, and scope of the present application. Explanation of the symbols

[0559] 1: Battery pack 2: Upper box 3: Bottom box 4: Battery Module 5: Battery cell 51: Case 52: Electrode assembly 53: Cover plate 6: Electrical device

Claims

Claim 1 A battery cell comprises a negative electrode sheet, wherein the negative electrode sheet comprises a negative current collector and a negative film layer installed on at least one side of the negative current collector, and the negative film layer comprises a negative active material and a negative dispersant, wherein the negative dispersant comprises a modified carboxymethylcellulose salt, and the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A. Formula A, where Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + A battery cell comprising at least one of the following; R comprises a hydrogen atom or a flexible group, wherein the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group. Claim 2 In claim 1, the battery cell, wherein the structural unit represented by Formula A includes the structural unit represented by Formula A-1. Formula A-1 Claim 3 In claim 1, the battery cell, wherein the structural unit represented by Formula A comprises the structural unit represented by Formula A-2. Formula A-2 Claim 4 In any one of claims 1 to 3, the cathodic dispersant further comprises a structural unit represented by Formula B, and Equation B, where M2 is a metal ion or NH4 + A battery cell comprising at least one of the following. Claim 5 A battery cell according to any one of claims 1 to 4, wherein, based on the total quantity of the structural unit represented by formula A and the structural unit represented by formula B, the quantity share of the structural unit represented by formula A is 0.5% to 20%. Claim 6 A battery cell according to claim 5, wherein, based on the total quantity of the structural unit represented by formula A and the structural unit represented by formula B, the quantity share of the structural unit represented by formula A is 1% to 10%. Claim 7 A battery cell according to any one of claims 1 to 6, wherein the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group. Claim 8 In claim 7, the substituted or unsubstituted C3 to C150 ether group comprises a structural formula represented by Formula 1, and Equation 1, in Equation 1, R 11 to R 17 A battery cell comprising, each independently comprising at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group; wherein m comprises any positive integer among 5 to 60. Claim 9 In claim 7 or 8, the substituted or unsubstituted C3 to C150 ether group comprises at least one of the structural formulas represented by Formula 1-1 to Formula 1-14, and Equation 1-1, Equation 1-2, Equation 1-3, Equation 1-4, Equation 1-5, Equation 1-6, Equation 1-7, Equation 1-8, Equation 1-9, Equation 1-10, Equation 1-11, Equation 1-12, Equation 1-13, Formula 1-14, m1 is a battery cell comprising any positive integer from 1 to 30. Claim 10 In any one of claims 7 to 9, the substituted or unsubstituted C3 to C150 alkyl group comprises a structural formula represented by Formula 2, and Equation 2, in Equation 2, R 21 to R 27 A battery cell comprising, each independently comprising at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group; and s comprising any positive integer among 5 to 60. Claim 11 In any one of claims 7 to 10, the substituted or unsubstituted C3 to C150 alkyl group comprises at least one of the structural formulas represented by Formula 2-1 to Formula 2-11, and Equation 2-1, Equation 2-2, Equation 2-3, Equation 2-4, Equation 2-5, Equation 2-6, Equation 2-7, Equation 2-8, Equation 2-9, Equation 2-10, Equation 2-11, s1 is a battery cell comprising any positive integer from 1 to 30. Claim 12 In any one of claims 7 to 11, the substituted or unsubstituted C3 to C150 polyolefin group comprises a structural formula represented by Formula 3, and Equation 3, in Equation 3, R 31 to R 34 Each independently comprises at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C2 to C10 alkenyl group; R 35 A battery cell comprising at least one of a hydrogen atom, a halogen atom, and a substituted or unsubstituted C1 to C10 alkyl group; wherein p comprises any positive integer from 5 to 60. Claim 13 A battery cell according to any one of claims 7 to 11, wherein the substituted or unsubstituted C3 to C150 polyolefin group comprises at least one of the structural formulas represented by Formula 3-1 to Formula 3-8. Equation 3-1, Equation 3-2, Equation 3-3, Equation 3-4, Equation 3-5, Equation 3-6, Equation 3-7, Equation 3-8 Claim 14 In any one of claims 7 to 13, the substituted or unsubstituted C3 to C150 amide group comprises a structural formula represented by Formula 4, and Equation 4, in Equation 4, R 41 ... comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group; R 42 to R 46 A battery cell comprising, each independently, at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group; wherein a comprises any positive integer from 1 to 30. Claim 15 A battery cell according to claim 14, wherein R41 comprises a single bond, and the substituted or unsubstituted C3 to C150 amide group comprises the structural formula represented by Formula 4-1. Equation 4-1 Claim 16 A battery cell according to claim 15, wherein the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-11 to Formula 4-15. Equation 4-11, Equation 4-12, Equation 4-13, Equation 4-14, Equation 4-15 Claim 17 In Paragraph 14, R 41 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and said substituted or unsubstituted C3 to C150 amide groups comprise the structural formula represented by Formula 4-2, Equation 4-2, a1 is a battery cell comprising any positive integer from 1 to 5. Claim 18 A battery cell according to claim 17, wherein the substituted or unsubstituted C3 to C150 amide group comprises at least one of the structural formulas represented by Formula 4-21 to Formula 4-24. Equation 4-21, Equation 4-22, Equation 4-23, Equation 4-24 Claim 19 In any one of claims 7 to 18, the substituted or unsubstituted C3 to C150 ester group comprises a structural formula represented by Formula 5, and Equation 5, in Equation 5, R 51 ... comprises at least one of a single bond, substituted, or unsubstituted C1 to C5 methylene group; R 52 comprises a substituted or unsubstituted C1 to C5 alkyl group; R 53 to R 55 A battery cell comprising: each independently comprising at least one of a hydrogen atom, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C2 to C10 alkenyl group, and a substituted or unsubstituted C2 to C10 alkynyl group; and b comprising any positive integer from 1 to 30. Claim 20 In Paragraph 19, R 51 A battery cell comprising a single bond, wherein the substituted or unsubstituted C3 to C150 ester group comprises the structural formula represented by Formula 5-1. Equation 5-1 Claim 21 A battery cell according to claim 20, wherein the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-11 to Formula 5-16. Equation 5-11, Equation 5-12, Equation 5-13, Equation 5-14, Equation 5-15, Equation 5-16 Claim 22 In Paragraph 19, R 51 ... comprises substituted or unsubstituted C1 to C5 methylene groups, and said substituted or unsubstituted C3 to C150 ester groups comprise the structural formula represented by Formula 5-2, Equation 5-2,b1 is a battery cell comprising any positive integer from 1 to 5. Claim 23 A battery cell according to claim 22, wherein the substituted or unsubstituted C3 to C150 ester group comprises at least one of the structural formulas represented by Formula 5-21 to Formula 5-28. Equation 5-21, Equation 5-22, Equation 5-23, Equation 5-24, Equation 5-25, Equation 5-26, Equation 5-27, Equation 5-28 Claim 24 A battery cell according to any one of claims 1 to 23, wherein the weight average molecular weight of the cathode dispersant is 40 wDa to 80 wDa. Claim 25 A battery cell according to any one of claims 1 to 24, wherein the elongation at break of the reference adhesive film made of sodium carboxymethylcellulose is 100%, the elongation at break of the adhesive film made of the modified carboxymethylcellulose salt is 225% to 400%, and the width of the adhesive film made of the cathode dispersant and the reference adhesive film is 2.5 cm, the length is 5 cm, and the thickness is 1 mm. Claim 26 A battery cell according to any one of claims 1 to 25, wherein the mass content of the modified carboxymethylcellulose salt is 0.8% to 1.3% based on the total mass of the cathode film layer. Claim 27 A battery cell according to claim 26, wherein the mass content of the modified carboxymethylcellulose salt is 1.0% to 1.2% based on the total mass of the cathode film layer. Claim 28 In any one of claims 1 to 27, the coating basis weight of the cathode film layer is 200 mg / 1540.25 mm 2 Up to 280 mg / 1540.25 mm 2 Phosphorus, battery cell. Claim 29 In claim 28, the coating basis weight of the cathode film layer is 220 mg / 1540.25 mm 2 Up to 280 mg / 1540.25 mm 2 Phosphorus, battery cell. Claim 30 A cathodic dispersant comprises a modified carboxymethylcellulose salt, wherein the modified carboxymethylcellulose salt comprises a structural unit represented by Formula A, and Formula A, where Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + A cathodic dispersant comprising at least one of the following; R comprises a hydrogen atom or a flexible group, wherein the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group. Claim 31 In paragraph 30, the cathodic dispersant comprises a structural unit represented by the above formula A, wherein the structural unit represented by the above formula A-1. Formula A-1 Claim 32 A cathodic dispersant according to claim 30 or 31, wherein the structural unit represented by Formula A comprises the structural unit represented by Formula A-2. Formula A-2 Claim 33 In any one of claims 30 to 32, the cathodic dispersant further comprises a structural unit represented by Formula B, and Equation B, where M2 is a metal ion or NH4 + A cathodic dispersant comprising at least one of the following. Claim 34 A cathodic dispersant according to any one of claims 30 to 33, wherein, based on the total quantity of the structural unit represented by Formula A and the structural unit represented by Formula B, the quantity share of the structural unit represented by Formula A is 0.5% to 20%. Claim 35 A cathodic dispersant according to claim 34, wherein, based on the total quantity of the structural unit represented by formula A and the structural unit represented by formula B, the quantity share of the structural unit represented by formula A is 1% to 10%. Claim 36 A cathodic dispersant according to any one of claims 30 to 35, wherein the flexible group comprises at least one of a substituted or unsubstituted C3 to C150 ether group, a substituted or unsubstituted C3 to C150 alkyl group, a substituted or unsubstituted C3 to C150 polyolefin group, a substituted or unsubstituted C3 to C150 amide group, or a substituted or unsubstituted C3 to C150 ester group. Claim 37 In the modified carboxymethylcellulose salt, it comprises a structural unit represented by Formula A, Formula A, where Q contains a hydrogen atom or -CH2COOM1, and M1 contains a metal ion or NH4 + A modified carboxymethylcellulose salt comprising at least one of the following; R comprises a hydrogen atom or a flexible group, wherein the flexible group comprises at least one of a substituted or unsubstituted ether group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted polyolefin group, a substituted or unsubstituted amide group, or a substituted or unsubstituted ester group. Claim 38 A cathode sheet comprising a cathode current collector and a cathode film layer installed on at least one surface of the cathode current collector, wherein the cathode comprises a cathode dispersant according to any one of claims 30 to 36. Claim 39 A battery comprising a battery cell according to any one of claims 1 to 29. Claim 40 An electric device comprising a battery according to paragraph 39.

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