Entropy and enthalpy conversion battery safety system and preparation method thereof

Abstract

The invention belongs to the technical field of lithium battery safety systems, and particularly discloses an entropy and enthalpy conversion battery safety system and a preparation method thereof. The entropy enthalpy conversion battery safety system comprises at least one naked battery cell and at least two abrupt change entropy enthalpy systems; the naked battery core and the abrupt-change enthalpy-capacity system are sequentially stacked and arranged in the battery shell; a gap in the shell is filled with a high-heat-capacity low-entropy-enthalpy filling material; the positive current collectors and the negative current collectors of every two adjacent naked battery cells are connected in parallel inside or outside the naked battery cells to form a low-voltage capacitance entropy and enthalpy conversion battery safety system; and the positive current collector of each naked battery cell is connected in series with the negative current collector of the adjacent naked battery cell inside or outside the naked battery cell to form a high-voltage capacity entropy and enthalpy conversion battery safety system. The chemical problems are solved by a chemical method, the conventional method for solving the chemical problems by a physical method in the current battery industry is broken, the potential safety hazard problem of the battery is thoroughly solved, and the preparation method is low in cost and suitable for producing and manufacturing the lithium battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium battery safety systems, and relates to an entropy-enthalpy conversion battery safety system and a preparation method thereof. Background Art

[0002] As a core technology for modern energy storage, lithium battery energy storage is widely used in various fields. At the same time, the frequent occurrence of lithium battery combustion and explosion accidents has made its safety issues a key concern for researchers.

[0003] Currently, physical methods such as safety valves, BMS management systems, and liquid cooling systems are used to improve the safety of lithium-ion batteries. However, a lithium-ion battery is an energy storage device, and the flash discharge of storing 1 kWh of electrical energy is equivalent to the power of a 0.86 kg TNT explosive package, that is to say, combustion and explosion are the basic properties of lithium-ion batteries. The combustion and explosion of lithium-ion batteries is a chemical reaction, and the reaction speed of using physical methods to solve the safety hazards of chemical reactions simply cannot adapt. The frequent occurrence of lithium-ion battery combustion and explosion accidents also proves the limitations of using physical solutions to solve the safety problems of lithium-ion batteries; in addition, the existing physical solutions are complex in process, low in efficiency, large in the amount of component consumables, and high in production cost.

[0004] It can be seen that the safety problem of lithium-ion battery energy storage has become the core obstacle restricting the systematic development of the new energy economy. Summary of the Invention

[0005] The purpose of the present invention is to provide an entropy-enthalpy conversion battery safety system to break the current convention of using physical methods to solve chemical problems in the battery industry in the way of using chemical methods to solve chemical problems, and completely solve the battery safety hazard problems.

[0006] The second purpose of the present invention is to provide a preparation method for the entropy-enthalpy conversion battery safety system, which is used to prepare the above-mentioned entropy-enthalpy conversion battery safety system, and the preparation method has low cost and is suitable for large-scale industrial production.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: An entropy-enthalpy conversion battery safety system includes the first to the mth bare battery cells and the first to the (m + 1)th mutation entropy-enthalpy systems, where m ≥ 1; The bare battery cell is composed of a positive current collector, a positive electrode film, a separator, a negative electrode film, a negative current collector, and an electrolyte; The bare battery cells and the mutation entropy-enthalpy systems are stacked in sequence and installed in a battery housing; the positive current collector and the negative current collector of the bare battery cells are exposed outside the battery housing; the stacking rule is: the pth bare battery cell is located between the pth mutation entropy-enthalpy system and the (p + 1)th mutation entropy-enthalpy system; where 1 ≤ p ≤ m; The voids in the shell are filled with a high heat capacity and low entropy enthalpy filling material; When m>1, the positive current collector of the nth bare cell, the positive current collector of the n+1th bare cell, the negative current collector of the nth bare cell and the negative current collector of the n+1th bare cell are connected in parallel inside or outside the bare cell to form a low-pressure capacity-entropy-enthalpy conversion battery safety system; the positive current collector of the nth bare cell and the negative current collector of the n+1th bare cell are connected in series inside or outside the bare cell to form a high-pressure capacity-entropy-enthalpy conversion battery safety system, where 1≤n≤m-1.

[0008] As a limitation, the sudden change capacity-entropy-enthalpy system is a sheet-shaped sudden change capacity-entropy-enthalpy system made by mixing Al(OH)3, CuSO4·5H2O, Na2CO3·10H2O, KAl(SO4)2·12H2O, and ZnSO4·7H2O in a molar ratio of 1:1~5:1~5:1~5:1~5, and then vacuum-packaging it with a temperature sensor membrane without gaps.

[0009] As a further limitation, the temperature sensor film is made of a temperature-sensitive material such as poly (N-isopropylacrylamide), polyacrylamide, polyacrylic acid, polyethyleneimine, polylactic acid-glycolic acid or poly (hydroxyethyl methacrylate) modified PP, PE, PET or PVD.

[0010] As a second limitation, the high heat capacity and low entropy enthalpy filling material is at least one of metal oxides, metal hydroxides, CuSO4•5H2O, CaSO4•2H2O, 2CaSO4•H2O, CuSO4•5H2O, Na2CO3•10H2O, FeSO4•7H2O, KAl(SO4)2•12H2O, and ZnSO4•7H2O.

[0011] As the third limitation, the battery casing is an open waterproof casing, the interior of which meets the IP68 waterproof performance requirements by filling bare batteries, a sudden change capacity-entropy-enthalpy system, and high heat capacity and low entropy-enthalpy filling materials.

[0012] As a further limitation of the temperature sensor membrane, the bare battery cell is connected to the adjacent sudden change capacity-entropy-enthalpy system through the temperature sensor membrane of the sudden change capacity-entropy-enthalpy system.

[0013] As another limitation of the temperature sensor membrane, the temperature sensor membrane breaks at the set temperature and releases high heat capacity and low entropy enthalpy substances, causing a sudden change in the system's capacity-entropy enthalpy. In the process of the system's capacity-entropy enthalpy increase and decrease rate being offset, the capacity-entropy enthalpy balance constitutes a new battery safety system.

[0014] The present invention also discloses a method for preparing the above-mentioned capacity-entropy-enthalpy conversion battery safety system, which comprises the following steps performed in sequence: S1. Prepare the first to the mth bare battery cells and the first to the (m + 1)th mutation capacitance entropy enthalpy systems; The preparation process of the pth bare battery cell is to stack and compound a positive current collector, a positive electrode film containing an electrolyte, a separator, a negative electrode film containing an electrolyte, and a negative current collector in sequence to prepare a bare battery cell; S2. Stack and arrange the bare battery cells and the mutation capacitance entropy enthalpy systems in sequence, install them in a battery housing, and expose the positive current collector and the negative current collector. Then, fill the voids in the battery housing with a high heat capacity and low entropy enthalpy filling material; The rule of stacking arrangement is that the pth bare battery cell is located between the pth mutation capacitance entropy enthalpy system and the (p + 1)th mutation capacitance entropy enthalpy system; In the above manufacturing process, when m > 1, the positive current collectors of the nth and (n + 1)th bare battery cells, the negative current collectors of the nth and (n + 1)th bare battery cells are connected in parallel inside or outside the bare battery cells to form a low - voltage capacitance entropy enthalpy conversion battery safety system, serving as a large - capacity single battery or a large - capacity battery module; the positive current collector of the nth bare battery cell and the negative current collector of the (n + 1)th bare battery cell are connected in series inside or outside the bare battery cells to form a high - voltage capacitance entropy enthalpy conversion battery safety system, serving as a high - voltage energy module or a battery PACK.

[0015] As a limitation, wrap the positive current collector and the negative current collector exposed from the battery housing with insulating tape to ensure insulation between the positive current collector, the negative current collector and the battery housing.

[0016] Due to the adoption of the above - mentioned technical solutions, compared with the prior art, the technical progress achieved by the present invention lies in: (1) The capacitance entropy enthalpy conversion battery safety system provided by the present invention stacks the bare battery cells and the mutation capacitance entropy enthalpy systems in sequence and alternately, installs them in a battery housing and exposes the positive and negative current collectors. The voids are filled with a high heat capacity and low entropy enthalpy filling material to form a new capacitance entropy enthalpy conversion battery safety system with a high heat capacity and low entropy enthalpy conversion balance; it can break the routine of using physical methods to solve chemical problems in the current battery industry by means of solving chemical problems with chemical methods, and completely solve the battery safety hazard problem; further, the bare battery cell and the mutation capacitance entropy enthalpy system are connected into one body through a temperature sensor film; the temperature sensor film can break the film at a set temperature and release a high heat capacity and low entropy enthalpy substance to trigger a mutation of the system's capacitance entropy enthalpy. During the process of hedging the increase - and - decrease rate of the system's capacitance entropy enthalpy, a new battery safety system is formed by the capacitance entropy enthalpy balance, effectively constructing an electrochemical thermodynamics safety system and preventing the combustion and explosion accidents of lithium - ion batteries, and being suitable for large - scale industrial production and popularization and application; (2) The preparation method of the capacitance entropy enthalpy conversion battery safety system provided by the present invention has low cost and is suitable for large - scale industrial production.

[0017] The present invention belongs to the technical field of lithium battery safety systems and can improve the safety of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation to the present invention.

[0019] In the accompanying drawings: Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention; Figure 2 is a schematic structural diagram of the bare battery cell in Embodiment 1 of the present invention; Figure 3 is a schematic structural diagram of the mutation entropy enthalpy system in Embodiment 1 of the present invention.

[0020] In the figure: 1, bare battery cell; 11, positive current collector; 12, positive electrode film; 13, separator; 14, negative electrode film; 15, negative current collector; 2, mutation entropy enthalpy system; 21, temperature sensor film; 3, high heat capacity and low entropy enthalpy filling substance; 4, battery housing. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to explain and illustrate the present invention and are not used to limit the present invention.

[0022] Embodiment 1 This embodiment provides a capacitance entropy enthalpy conversion battery safety system, as Figures 1 to 3 shown, which includes the first to fourth bare battery cells 1 and the first to fifth mutation entropy enthalpy systems 2.

[0023] The bare battery cell 1 is composed of a positive current collector 11, a positive electrode film 12, a separator 13, a negative electrode film 14, a negative current collector 15 and an electrolyte. The mutation entropy enthalpy system 2 is: Al(OH)3, CuSO4·5H2O, Na2CO3·10H2O, KAl(SO4)2·12H2O, ZnSO4·7H2O are mixed in a molar ratio of 1:1:1:1:1, and then vacuum-sealed without gaps with the temperature sensor film 21 to form a sheet-like mutation entropy enthalpy system 2.

[0024] The bare cell 1 and the sudden capacitance-entropy-enthalpy system 2 are stacked and arranged in sequence and installed in the battery casing 4. The positive current collector 11 and the negative current collector 15 of the bare cell 1 are exposed from the battery casing 4. The stacking arrangement rule is: the pth bare cell 1 is located between the pth sudden capacitance-entropy-enthalpy system 2 and the p+1th sudden capacitance-entropy-enthalpy system 2; wherein, 1≤p≤4. The bare cell 1 is connected to the adjacent sudden capacitance-entropy-enthalpy system 2 through the temperature sensor film 21 of the sudden capacitance-entropy-enthalpy system 2. The gap in the battery casing 4 is filled with a high heat capacity and low entropy enthalpy filling material 3.

[0025] The positive current collector 11 of the nth bare cell 1, the positive current collector 11 of the n+1th bare cell 1, the negative current collector 15 of the nth bare cell 1 and the negative current collector 15 of the n+1th bare cell 1 are connected in parallel inside or outside the bare cell 1 to form a low-pressure capacity-entropy-enthalpy conversion battery safety system, which serves as a large-capacity single cell or a large-capacity battery module. The positive current collector 11 of the nth bare cell 1 and the negative current collector 15 of the n+1th bare cell 1 are connected in series inside or outside the bare cell 1 to form a high-voltage capacity-entropy-enthalpy conversion battery safety system, which serves as a high-voltage energy module or battery PACK. Wherein, 1≤n≤3.

[0026] In this embodiment, the positive current collector 11 of each two adjacent bare cells 1 and the negative current collector 15 of each two adjacent bare cells 1 are connected in parallel inside the bare cell 1 to form a low-voltage capacity-entropy-enthalpy conversion battery safety system, serving as a 100Ah / 3.2V large-capacity single cell. The positive current collector 11 of each bare cell 1 and the negative current collector 15 of the adjacent bare cell 1 are connected in series inside the bare cell 1 to form a high-voltage capacity-entropy-enthalpy conversion battery safety system, serving as a 25Ah / 12.8V high-voltage energy module.

[0027] The temperature sensor membrane 21 can be made of modified PP, PE, PET or PVD of poly N-isopropylacrylamide, polyacrylamide, polyacrylic acid, polyethyleneimine, polylactic acid-glycolic acid or polyhydroxyethyl methacrylate, so that it breaks the membrane at 135°C ± 3°C and loses protection for the high heat capacity and low entropy enthalpy substances inside. When the temperature sensor membrane 21 is punctured, impacted, overcharged, over-discharged, overheated or other abnormal damages to the battery, the battery will produce rapid enthalpy drop and entropy increase, that is, rapid temperature rise and then explosion, that is, the temperature reaches 135°C ± 3°C before the battery explodes, the membrane breaks and releases high heat capacity and low entropy enthalpy substances to cause a sudden change in system capacity entropy enthalpy. At this time, the system heat capacity suddenly increases significantly, the battery temperature rise rate decreases rapidly, and the enthalpy drop entropy growth rate is offset and balanced, that is, the free energy of the chemical reaction to maintain the explosion is rapidly increased to zero to interrupt the explosion chemical reaction, and the battery enters a safe state.

[0028] In this embodiment, the temperature sensor film 21 is made of modified PP of the temperature-sensitive material poly(N-isopropylacrylamide) (PNIPAM). The film-breaking temperature of the temperature sensor film 21 is set at 135°C ± 3°C. The temperature sensor film 21 can break the film within the range of the set temperature of 135°C ± 3°C and release high heat capacity and low entropy enthalpy substances to trigger a mutation of the system's entropy enthalpy. During the process of hedging the increase and decrease rate of the system's entropy enthalpy, a new battery safety system is formed by the balance of entropy enthalpy, with smoke but no combustion or explosion.

[0029] In this embodiment, the battery housing 4 is an open waterproof housing, and its interior meets the IP68 waterproof performance requirements by filling the bare battery cells 1, the mutation entropy enthalpy system 2, and the high heat capacity and low entropy enthalpy filling substance 3. Among them, the high heat capacity and low entropy enthalpy filling substance 3 is composed of a mixture of Al2O3, CuSO4•5H2O, gypsum CaSO4•2H2O, plaster of Paris 2CaSO4•H2O, CuSO4•5H2O, Na2CO3•10H2O, FeSO4•7H2O, KAl(SO4)2•12H2O, and ZnSO4•7H2O. In actual production, the high heat capacity and low entropy enthalpy filling substance 3 is at least one of metal oxides, metal hydroxides, CuSO4•5H2O, CaSO4•2H2O, 2CaSO4•H2O, CuSO4•5H2O, Na2CO3•10H2O, FeSO4•7H2O, KAl(SO4)2•12H2O, and ZnSO4•7H2O. Which specific material combinations are used need to be determined according to actual production needs.

[0030] This embodiment only uses four bare battery cells 1 and five mutation entropy enthalpy systems 2 as examples for illustration. In actual production, the number of bare battery cells 1 is at least one, and the number of mutation entropy enthalpy systems 2 is one more than the number of bare battery cells 1, which can be determined according to actual production needs.

[0031] Similarly, the mutation entropy enthalpy system 2 is prepared by mixing Al(OH)3, CuSO4·5H2O, Na2CO3·10H2O, KAl(SO4)2·12H2O, and ZnSO4·7H2O in a molar ratio of 1 to 5:1 to 5:1 to 5:1 to 5:1 to 5, and then vacuum-packaging it without gaps with the temperature sensor film 21 to form a sheet-like mutation entropy enthalpy system 2, which can be reasonably proportioned according to actual production needs.

[0032] Embodiment 2 This embodiment provides a preparation method for Embodiment 1, and the preparation method includes the following steps carried out in sequence: S1. Prepare the first to fourth bare battery cells 1 and the first to fifth mutation entropy enthalpy systems 2; Among them, the preparation process of each bare battery cell 1 is to stack and compound a positive current collector 11, a positive electrode film 12 containing an electrolyte, a separator 13, a negative electrode film 14 containing an electrolyte, and a negative current collector 15 in sequence to prepare the bare battery cell 1; The preparation process of the mutation capacitance entropy enthalpy system 2 is as follows: After mixing Al(OH)3, CuSO4·5H2O, Na2CO3·10H2O, KAl(SO4)2·12H2O, and ZnSO4·7H2O in a molar ratio of 1:1:1:1:1, it is then vacuum-sealed without gaps with a temperature sensor film 21 to form a sheet-like mutation capacitance entropy enthalpy system 2; S2. The positive current collectors 11 of every two adjacent bare battery cells 1 and the negative current collectors 15 of every two adjacent bare battery cells 1 are connected in parallel inside the bare battery cell 1 to form a low-voltage capacitance entropy enthalpy conversion battery safety system as a large-capacity single battery; the positive current collector 11 of each bare battery cell 1 is connected in series with the negative current collector 15 of the adjacent bare battery cell 1 inside the bare battery cell 1 to form a high-voltage capacitance entropy enthalpy conversion battery safety system as a high-voltage energy module.

[0033] S3. The bare battery cells 1 and the mutation capacitance entropy enthalpy systems 2 are stacked and arranged in sequence, placed in a battery case 4, and the positive current collector 11 and the negative current collector 15 are exposed. The exposed positive current collector 11 and negative current collector 15 of the battery case 4 are wrapped with insulating tape to ensure that the positive current collector 11 and the negative current collector 15 are insulated from the battery case 4; then the voids inside the battery case 4 are filled with a high heat capacity and low entropy enthalpy filling material 3; The stacking and arranging rule is: The p-th bare battery cell 1 is located between the p-th mutation capacitance entropy enthalpy system 2 and the (p + 1)-th mutation capacitance entropy enthalpy system 2.

Claims

1. A safety system for a capacity entropy-enthalpy conversion battery, characterized in that, It includes the first to mth bare cells and the first to m+1th sudden change capacity entropy enthalpy systems, wherein m≥1; The bare cell consists of a positive electrode current collector, a positive electrode film, a separator, a negative electrode film, a negative electrode current collector and an electrolyte; The bare cells and the sudden change capacity-entropy-enthalpy system are stacked and arranged in sequence and installed in a battery casing; the positive current collector and the negative current collector of the bare cells are exposed from the battery casing; the stacking arrangement rule is: the pth bare cell is located between the pth sudden change capacity-entropy-enthalpy system and the p+1th sudden change capacity-entropy-enthalpy system; wherein 1≤p≤m; The voids in the shell are filled with a high heat capacity and low entropy enthalpy filling material; When m>1, the positive current collector of the nth bare cell, the positive current collector of the n+1th bare cell, the negative current collector of the nth bare cell and the negative current collector of the n+1th bare cell are connected in parallel inside or outside the bare cell to form a low-pressure capacity-entropy-enthalpy conversion battery safety system; the positive current collector of the nth bare cell and the negative current collector of the n+1th bare cell are connected in series inside or outside the bare cell to form a high-pressure capacity-entropy-enthalpy conversion battery safety system, where 1≤n≤m-1.

2. The entropy capacity - enthalpy conversion battery safety system according to claim 1, characterized in that The sudden change capacity-entropy-enthalpy system is a sheet-shaped sudden change capacity-entropy-enthalpy system prepared by mixing Al(OH)3, CuSO4·5H2O, Na2CO3·10H2O, KAl(SO4)2·12H2O and ZnSO4·7H2O in a molar ratio of 1:1-5:1-5:1-5:1-5:1-5 and then vacuum-packaging with a temperature sensor film without gaps.

3. The entropy capacity-enthalpy conversion battery safety system according to claim 2, characterized in that, The temperature sensor membrane adopts the temperature-sensitive material poly (N-isopropylacrylamide), polyacrylamide, polyacrylic acid, polyethyleneimine, polylactic acid-glycolic acid or modified PP, PE, PET or PVD of poly (hydroxyethyl methacrylate).

4. The entropy capacity - enthalpy conversion battery safety system according to claims 1 to 3, characterized in that, The high heat capacity and low entropy enthalpy filling material is at least one of metal oxides, metal hydroxides, CuSO4•5H2O, CaSO4•2H2O, 2CaSO4•H2O, CuSO4•5H2O, Na2CO3•10H2O, FeSO4•7H2O, KAl(SO4)2•12H2O, and ZnSO4•7H2O.

5. The entropy-enthalpy conversion battery safety system according to claims 1 to 3, characterized in that, The battery shell is an open waterproof shell, and its interior meets the IP68 waterproof performance requirements by filling bare batteries, a sudden change capacity-entropy-enthalpy system, and high heat capacity and low entropy-enthalpy filling materials.

6. The entropy-enthalpy conversion battery safety system according to claim 2 or 3, characterized in that, The bare battery cell is connected to the adjacent sudden change capacity-entropy-enthalpy system through a temperature sensor membrane provided by the sudden change capacity-entropy-enthalpy system.

7. The entropy-enthalpy conversion battery safety system according to claim 2 or 3, characterized in that, The temperature sensor membrane breaks at the set temperature and releases high heat capacity and low entropy enthalpy substances, causing a sudden change in the system's capacity-entropy enthalpy. In the process of the system's capacity-entropy enthalpy increase and decrease rate being offset, the capacity-entropy enthalpy balance constitutes a new battery safety system.

8. The entropy capacity enthalpy conversion battery safety system according to claim 6, characterized in that, The temperature sensor membrane breaks at the set temperature and releases high heat capacity and low entropy enthalpy substances, causing a sudden change in the system's capacity-entropy enthalpy. In the process of the system's capacity-entropy enthalpy increase and decrease rate being offset, the capacity-entropy enthalpy balance constitutes a new battery safety system.

9. A preparation method of the content entropy-enthalpy conversion battery safety system according to any one of claims 1 to 8, characterized in that, The preparation method comprises the following steps which are carried out in sequence: S1. Prepare the first to mth bare cells and the first to m+1th sudden change capacity-entropy-enthalpy systems; The preparation process of the pth bare battery cell is to stack and compound a positive current collector, a positive electrode film containing an electrolyte, a separator, a negative electrode film containing an electrolyte, and a negative current collector in sequence to prepare a bare battery cell; S2. Stack and arrange the bare battery cell and the mutation capacitance entropy enthalpy system in sequence, install them in a battery case, expose the positive current collector and the negative current collector, and then fill the voids in the battery case with a high heat capacity and low entropy enthalpy filling material; The rule for stacking and arranging is that the pth bare battery cell is located between the pth mutation capacitance entropy enthalpy system and the (p + 1)th mutation capacitance entropy enthalpy system; In the above manufacturing process, when m > 1, the positive current collectors of the nth bare battery cell, the positive current collector of the (n + 1)th bare battery cell, the negative current collector of the nth bare battery cell, and the negative current collector of the (n + 1)th bare battery cell are connected in parallel inside or outside the bare battery cell to form a low-voltage capacitance entropy enthalpy conversion battery safety system, which serves as a large-capacity single battery or a large-capacity battery module; the positive current collector of the nth bare battery cell and the negative current collector of the (n + 1)th bare battery cell are connected in series inside or outside the bare battery cell to form a high-voltage capacitance entropy enthalpy conversion battery safety system, which serves as a high-voltage energy module or a battery PACK.

10. The preparation method according to claim 9, wherein, Wrap the exposed positive current collector and negative current collector of the battery case with insulating tape to ensure insulation between the positive current collector, negative current collector and the battery case.

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