Battery module, battery pack, electric apparatus, and method and device for manufacturing battery module

1. A battery module, comprising a first type of battery cells and a second type of battery cells connected at least in series, wherein the first type of battery cells and the second type of battery cells are battery cells of different chemical system,

the first type of battery cells comprises N first battery cells,

the second type of battery cells comprises M second battery cells, and N and M are positive integers;

a positive electrode plate of the second battery cell contains two or more positive electrode active materials, and when a dynamic SOC of the second battery cell is in a range from 90% to 98%, a change rate ΔOCV/ΔSOC in an OCV relative to the SOC of the second battery cell satisfies: 3≤ΔOCV/ΔSOC≤9, in mV/% SOC, where SOC represents a charge state and OCV represents an open circuit voltage, and when a dynamic SOC of the battery module is in the range from 90% to 98%, a ratio Q of ΔOCV/ΔSOC of the second battery cell to ΔOCV/ΔSOC of the first battery cell is 2≤Q≤40,

wherein

the positive electrode active material of the first battery cell comprises a lithium-containing phosphate represented by formula (III),

LiFe1 −x 3 −y 3Mn x 3M″ y 3PO4  formula (III)

in formula (III), 0≤x3≤1, 0≤y3≤0.1, and M′ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn,

or

the positive electrode active material of the first battery cell comprises a layered lithium transition metal oxide represented by formula (IIII),

Li1 +x 4Ni a 2Co b 2M3 c 2M41 −a 2 −b 2 −c 2O2 −y 4A2 y 4  formula (IIII)

in formula (IIII), −0.1≤x4≤0.2, 0.3≤a2<0.95, 0<b2<0.3, 0<a2+b2+c2<1, 0≤y4<0.2, M3 is at least one selected from Mn and Al, M4 is one or more selected from Fe, Cr, Ti, Zn, V, Al, Zr and Ce, and A2 is one or more selected from S, F, Cl and I, and

wherein

the positive electrode active material of the second battery cell comprises at least a layered lithium transition metal oxide represented by formula (I) and a lithium-containing phosphate represented by formula (II),

Li1 +x 1Ni a 1Co b 1M1 c 1M21 −a 1 −b 1 −c 1O2 −y 1A1 y 1  formula (I)

LiFe1 −x 2 −y 2Mn x 2M′ y 2PO4  formula(II)

in formula (I), −0.1≤x1≤0.2, 0.3≤a1<0.97, 0<b1≤0.3, 0<a1+b1+c1<1, 0≤y1<0.2, M1 is at least one selected from Mn and Al, M2 is one or more selected from Fe, Cr, Ti, Zn, V, Al, W, Mg, B, Cu, Y, Si, Sr, Zr and Ce, and Al is one or more selected from S, N, F, Cl, Br, PO43- and I; and

in formula (II), 0≤x2≤1, 0≤y2≤0.1, and M′ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn.

2. The battery module according to claim 1 , wherein

when the dynamic SOC of the second battery cell is in the range from 90% to 98%, the change rate ΔOCV/ΔSOC in the OCV relative to the SOC of the second battery cell satisfies: 3.5≤ΔOCV/ΔSOC≤7, in mV/% SOC.

3. The battery module according to claim 1 , wherein when the dynamic SOC of the second battery cell is in a range from 30% to 80%, the change rate ΔOCV/ΔSOC in the OCV relative to the SOC of the second battery cell satisfies: ΔOCV/ΔSOC≤1, in mV/% SOC.

4. The battery module according to claim 1 , wherein

a discharge battery balance rate CB2 of the second battery cell satisfies 1.00≤CB2≤1.16.

5. The battery module according to claim 1 , wherein in formula (I), 0.5≤a1≤0.7, and 0.01≤b1≤0.15; and

in formula (II), 0≤x2≤0.5.

6. The battery module according to claim 5 , wherein

in the positive electrode active material of the second battery cell, the layered lithium transition metal oxide represented by formula (I) has a mass percentage from 0.5 wt % to 30 wt %.

7. The battery module according to claim 1 , wherein the first battery cell satisfies condition 1 and condition 2,

condition 1: when the dynamic SOC of the battery module is in the range from 90% to 98%, the ratio Q of ΔOCV/ΔSOC of the second battery cell to ΔOCV/ΔSOC of the first battery cell is 2<Q≤40;

condition 2: when the dynamic SOC of the first battery cell is in the range from 30% to 80%, the change rate ΔOCV/ΔSOC in the OCV relative to the SOC of the first battery cell satisfies ΔOCV/ΔSOC≤0.25, in mV/% SOC.

8. The battery module according to claim 1 , wherein

the discharge battery balance rate CB1 of the first battery cell satisfies 1.00≤CB1≤1.18.

9. The battery module according to claim 1 , wherein

the positive electrode active material of the first battery cell comprises one or more of LiFePO4, LiMnPO4, LiMn1−x3Fex3PO4, and LiV1−x3Fex3PO4, where x3 independently satisfies 0<x3<1.

10. A battery pack, comprising the battery module according to claim 1 .

11. An electric apparatus, comprising the battery module according to claim 1 , wherein the battery module or the battery pack is used as a power source or an energy storage unit of the electric apparatus.

12. An electric apparatus, comprising the battery pack according to claim 10 , wherein the battery module or the battery pack is used as a power source or an energy storage unit of the electric apparatus.

13. A method for manufacturing a battery module, comprising the following steps:

obtaining a first type of battery cells and a second type of battery cells, wherein

the first type of battery cells and the second type of battery cells are battery cells of different chemical systems,

the first type of battery cells comprises N first battery cells,

the second type of battery cells comprises M second battery cells, N and M are positive integers,

the positive electrode plate of the second battery cell contains two or more than two positive electrode active materials, and when a dynamic SOC of the second battery cell is in a range from 90% to 98%, a change rate ΔOCV/ΔSOC in an OCV to the SOC of the second battery cell relative satisfies 3≤ΔOCV/ΔSOC≤9, where SOC represents a charge state and OCV represents an open circuit voltage, and when a dynamic SOC of the battery module is in the range from 90% to 98%, a ratio Q of ΔOCV/ΔSOC of the second battery cell to ΔOCV/ΔSOC of the first battery cell is 2≤Q≤40,

wherein

the positive electrode active material of the first battery cell comprises a lithium-containing phosphate represented by formula (III),

LiFe1 −x 3 −y 3Mn x 3M″ y 3PO4  formula (III)

in formula (III), 0≤x3≤1, 0≤y3≤0.1, and M′ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn,

or

the positive electrode active material of the first battery cell comprises a layered lithium transition metal oxide represented by formula (IIII),

Li1 +x 4Ni a 2Co b 2M3 c 2M41 −a 2 −b 2 −c 2O2 −y 4A2 y 4  formula (IIII)

in formula (IIII), −0.1≤x4≤0.2, 0.3≤a2<0.95, 0<b2<0.3, 0<a2+b2+c2<1, 0≤y4<0.2, M3 is at least one selected from Mn and Al, M4 is one or more selected from Fe, Cr, Ti, Zn, V, Al, Zr and Ce, and A2 is one or more selected from S, F, Cl and I, and

wherein

the positive electrode active material of the second battery cell comprises at least a layered lithium transition metal oxide represented by formula (I) and a lithium-containing phosphate represented by formula (II),

Li1 +x 1Ni a 1Co b 1M1 c 1M21 −a 1 −b 1 −c 1O2 −y 1A1 y 1  formula (I)

LiFe1 −x 2 −y 2Mn x 2M′ y 2PO4  formula (II)

in formula (I), −0.1≤x1≤0.2, 0.3≤a1<0.97, 0<b1≤0.3, 0<a1+b1+c1<1, 0≤y1<0.2, M1 is at least one selected from Mn and Al, M2 is one or more selected from Fe, Cr, Ti, Zn, V, Al, W, Mg, B, Cu, Y, Si, Sr, Zr and Ce, and Al is one or more selected from S, N, F, Cl, Br, PO43- and I; and

in formula (II), 0≤x2≤1, 0≤y2≤0.1, and M′ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn; and

connecting the first type of battery cells and the second type of battery cells at least in series to form the battery module according to claim 1 .

14. A device for manufacturing a battery module, characterized in comprising:

a clamping arm unit, which is used to obtain a first type of battery cells and a second type of battery cells,

the first type of battery cells and the second type of battery cells are battery cells of different chemical systems,

the first type of battery cells comprises N first battery cells,

the second type of battery cells comprises M second battery cells, N and M are positive integers,

the positive electrode plate of the second battery cell contains two or more than two positive electrode active materials, and when a dynamic SOC of the second battery cell is in a range from 90% to 98%, a change rate ΔOCV/ΔSOC in an OCV relative to the SOC of the second battery cell satisfies 3≤ΔOCV/ΔSOC≤9, where SOC represents a charge state and OCV represents an open circuit voltage, and when a dynamic SOC of the battery module is in the range from 90% to 98%, a ratio Q of ΔOCV/ΔSOC of the second battery cell to ΔOCV/ΔSOC of the first battery cell is 2≤Q≤40,

wherein

the positive electrode active material of the first battery cell comprises a lithium-containing phosphate represented by formula (III),

LiFe1 −x 3 −y 3Mn x 3M″ y 3PO4  formula (III)

in formula (III), 0≤x3≤1, 0≤y3≤0.1, and M″ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn,

or

the positive electrode active material of the first battery cell comprises a layered lithium transition metal oxide represented by formula (IIII),

Li1 +x 4Ni a 2Co b 2M3 c 2M41 −a 2 −b 2 −c 2O2 −y 4A2 y 4  formula (IIII)

in formula (IIII), −0.1≤x4≤0.2, 0.3≤a2<0.95, 0<b2<0.3, 0<a2+b2+c2<1, 0≤y4<0.2, M3 is at least one selected from Mn and Al, M4 is one or more selected from Fe, Cr, Ti, Zn, V, Al, Zr and Ce, and A2 is one or more selected from S, F, Cl and I, and

wherein

the positive electrode active material of the second battery cell comprises at least a layered lithium transition metal oxide represented by formula (I) and a lithium-containing phosphate represented by formula (II),

Li1 +x 1Ni a 1Co b 1M1 c 1M21 −a 1 −b 1 −c 1O2 −y 1A1 y 1  formula (I)

LiFe1 −x 2 −y 2Mn x 2M′ y 2PO4  formula (II)

in formula (I), −0.1≤x1≤0.2, 0.3≤a1<0.97, 0<b1≤0.3, 0<a1+b1+c1<1, 0≤y1<0.2, M1 is at least one selected from Mn and Al, M2 is one or more selected from Fe, Cr, Ti, Zn, V, Al, W, Mg, B, Cu, Y, Si, Sr, Zr and Ce, and Al is one or more selected from S, N, F, Cl, Br, PO43- and I; and

in formula (II), 0≤x2≤1, 0≤y2≤0.1, and M′ is one or more selected from transition metal elements and non-transition metal elements other than Fe and Mn;

an assembling unit, which is used to connect the first type of battery cells and the second type of battery cells at least in series to form the battery module according claim 1 ; and

a control unit, which is used to control the clamping arm unit and the assembling unit.

15. The battery module according to claim 1 , wherein 4≤Q≤32.