CN106229587A - Lithium battery assembly capable of providing high discharge pulse in wide temperature range and forming method - Google Patents

Abstract

The rechargeable secondary lithium-ion battery disclosed in the present invention has improved anode materials, cathode materials and electrolytes to reduce the risk of lithium metal deposition on the surface of carbonaceous materials to form dendrites and the occurrence of side reactions when lithium ions are inserted into the carbonaceous materials during charging. The present invention also discloses a lithium battery assembly and a formation method that can provide high discharge pulses in a wide temperature range. The lithium battery assembly includes a primary lithium/halogen oxide battery and a rechargeable secondary lithium-ion battery connected in parallel with the primary lithium/halogen oxide battery. The open circuit voltage of the rechargeable secondary lithium-ion battery in a full state is higher than that of the primary lithium/halogen oxide battery in parallel. The lithium battery assembly of the present invention, because the open circuit voltage of the rechargeable secondary lithium-ion battery in a full state is higher than that of the primary lithium/halogen oxide battery in parallel, makes the two connected in parallel and the rechargeable secondary lithium-ion battery under the open circuit condition at the load end lower than the full state, thereby reducing the self-discharge phenomenon caused by aging and side reactions.

Description

Lithium battery assembly capable of providing high discharge pulses over a wide temperature range and method of forming the same

technical field

The invention relates to the technical field of lithium batteries, in particular to a lithium battery assembly capable of providing high discharge pulses in a wide temperature range and a forming method.

Background technique

With the rapid development of wireless communication technology, mobile devices have been fully digitized and their functions are becoming increasingly complex. Correspondingly, the demand for power in the working mode of the device is transformed into instantaneous high-current pulses for wireless data transmission. Taking the Global System for Mobile Communications (GSM) as an example, its typical demand is 2A, 500ms pulse current. Another example is the rapidly developing smart meter reading (AMR) system in recent years. It has the ability to automatically collect digital water and electricity meter readings, and regularly transmits data to mobile collection terminals through wireless communication, and further uploads to the central management platform. The power supply used in this type of AMR system should have the ability of long life, instantaneous high current discharge, and wide operating temperature and altitude range in response to outdoor conditions.

In traditional single-cell power systems for mobile devices, lithium/oxyhalide primary electrochemical batteries such as lithium/thionyl chloride (Li/SOCl ₂ ) or lithium/sulfuryl chloride (Li/SO ₂ Cl ₂ ) batteries are known for their high energy Density, long service life, and a relatively wide operating temperature range can serve as an important class of solutions. Typical power requirements of such systems generally include a continuous background current as low as several milliamps, and intermittent short current pulses ranging from tens of milliamps to several amperes, where the pulse width is at the millisecond level. However, under open-circuit or low-current conditions, the anode of a lithium/oxyhalide battery forms a passivation layer on the surface, severely reducing the available operating current of the battery. In this case, the high current discharge pulse will cause the battery output voltage to drop sharply to a lower level, unable to drive the corresponding power consumption device. By adding additives, such as polyvinyl chloride (Polyvinyl Chloride) and sulfur trioxide (SO ₃ ), to the battery electrolyte, the conductivity of the passivation layer can be improved to partially improve related problems, but the passivation process still exists. At the same time, the effect of additives will weaken within a few months over time. Compared with the working life of this type of battery for several years, the improvement of the overall battery performance is limited. Another possible solution includes changing the battery structure design from carbon-packed (Bobbin) to wound-type (Jelly-Roll) to obtain a larger electrode surface area to increase discharge power. However, this method not only cannot solve the problem of electrode passivation, but the battery has a high risk of explosion under certain conditions, such as short circuit, extrusion, puncture, etc.

As for other solutions, the combination of a capacitive device with high discharge power in parallel with a primary electrochemical cell is known in the art in order to increase the capacity for instantaneous discharge. A schematic diagram of a circuit 1 of the previous example is shown in FIG. 1 , which includes a primary electrochemical cell 2 and a capacitive device 3 connected in parallel thereto. This method can reduce the problem of voltage drop between the two access terminals 4 and 5 when a large current is discharged to a certain extent. The typical working mode of the circuit 1 is that the capacitor 3 is charged by the primary battery 2 until the two voltages are equal. When the connection terminals 4 and 5 are open, the primary battery 2 provides a small current to the capacitor 3 to compensate for its leakage current. When the load is connected between the access terminals 4 and 5 and the circuit 1 is required to provide a large current, part of the current can be output by the capacitor 3 so as to reduce the current demand for the primary battery 2 . Therefore, within the dischargeable capacity of the capacitor 3, the problem of low voltage output of the primary battery 2 due to high current discharge can be alleviated.

However, the scope of application of the above scheme is relatively small. The main reason is that if the voltage of the capacitor 3 is maintained at a specific level during the load duty cycle, the capacitor 3 is required to have a very large capacitance considering the pulse energy required by the aforementioned communication devices. Typical capacitors with extremely large capacitance values are prohibitively expensive and bulky for most applications.

In the previous WO patent 2007097534 (Chung Se-II et al.), the above capacitive device 3 is replaced by an electric double-layer capacitor (Electric Double-Layer Capacitor, EDLC) or a super capacitor. Supercapacitors have a much higher capacitance than common electrolytic capacitors (typically several hundred times the value of electrolytic capacitors under the same volume conditions), which can partially reduce the practical problems caused by bulky capacitors. Such replacements, however, do not solve the problem of leakage current. The capacity loss of supercapacitors due to their high self-discharge rate can reach 50%/month, much higher than the 5%/month of general lithium-ion batteries (Danilo Porcarelli et al., Networked Sensing Systems (INSS), 2012Ninth International Conference on, pagesl- 4, 2012). Considering the high capacitance value and corresponding high power storage capacity of supercapacitors, the relatively large leakage loss under open circuit conditions will seriously consume the capacity of the primary battery matched with it and affect the working life of the power supply.

US Patent 8,119,276 (Arden P. Johnson et al.) describes a composite power system in which a primary lithium/oxyhalide battery and a secondary lithium ion battery are connected in parallel. Replacing capacitors with secondary batteries can improve the problem of insufficient discharge capacity in communication applications. However, its power system specifically defines that "the open circuit voltage of the secondary battery is about 0.05V to about 0.8V lower than that of a brand new primary electrochemical battery in a fully charged state". Therefore, the rechargeable secondary battery in the previous example has the risk of being overcharged in the power source, resulting in safety problems such as electrolyte decomposition or short circuit. Although the composite power system may include a diode element connected in series between the primary battery and the secondary battery to protect the secondary battery. Since the voltage drop across the diode will change with time and usage conditions, the problem is not completely solved. In addition, under the ideal conditions of the foregoing example, the lithium-ion secondary battery is fully charged or slightly overcharged by the primary battery under the condition of no load on the power supply. However, when a lithium-ion battery is fully charged or overcharged, the surface of the anode is highly polarized, which makes side reactions more likely to occur, resulting in leakage and capacity loss, and ultimately shortens the service life of the battery system.

US Patent 5,998,052 (Yamin et al.) describes a hybrid power system comprising a primary battery and a secondary rechargeable battery. Similarly, secondary batteries instead of capacitors can improve the problem of insufficient discharge capacity in communication applications. However, the combination of the primary battery and the secondary battery is limited to: the secondary battery is placed in the primary battery, the primary battery is placed in the secondary battery, and the primary battery and the secondary battery are connected in parallel on the printed circuit board with conductive connections. This design makes the manufacturing process of the composite battery system complicated and expensive. At the same time, when any one of the batteries fails to work normally, it is difficult to replace the components, which further increases the maintenance cost in the application. In addition, there is no limitation on the structure of the secondary lithium ion battery in the foregoing examples. Considering the poor low-temperature performance of lithium-ion batteries (typical operating temperature > -10°C), this type of composite battery power supply has limited applications in fields such as outdoor communications and smart meter reading systems.

Contents of the invention

Embodiments of the present invention provide an improved composite power system based on the previous example, that is, a lithium battery assembly, which can provide high discharge pulses in a wide temperature range, and a method for forming the lithium battery assembly.

According to a first aspect of the present invention, the present invention provides a rechargeable secondary lithium ion battery with improved anode material, cathode material and electrolyte, so that various characteristics of the secondary lithium ion battery are greatly improved Improve and improve. Specifically, the rechargeable secondary lithium-ion battery includes a cathode material and an anode composite carbonaceous material, and the capacity of the above-mentioned cathode material to reversibly combine lithium ions with the above-mentioned anode composite carbonaceous material reversibly combines lithium ions in the form of LiC6 The capacity ratio is between 0.5:1 and 2:1 to reduce the risk of lithium metal deposition on the surface of the carbonaceous material to form dendrites and side reactions when lithium ions are inserted into the carbonaceous material during charging.

According to another aspect of the present invention, the present invention provides a lithium battery assembly capable of providing high discharge pulses over a wide temperature range, the lithium battery assembly comprising one or more primary lithium/oxyhalide batteries and rechargeable secondary batteries connected in parallel thereto. Secondary lithium-ion batteries; in particular, the open-circuit voltage of the rechargeable secondary lithium-ion battery in a fully charged state is higher than that of the above-mentioned primary lithium/oxyhalide batteries connected in parallel, so that the two can be connected in parallel and the load terminal is open. The voltage of the rechargeable secondary lithium-ion battery is lower than the voltage of the full state to reduce aging and self-discharge caused by side reactions.

As a further improved embodiment of the present invention, the above-mentioned rechargeable secondary lithium ion battery includes a cathode material and an anode composite carbonaceous material, and the above-mentioned cathode material reversibly combines the capacity of lithium ions with the above _- mentioned anode composite carbonaceous material in the form of LiC The capacity ratio of reversibly binding lithium ions is between 0.5:1 and 2:1 to reduce the risk of lithium metal deposition on the surface of the carbonaceous material to form dendrites and side reactions when lithium ions are inserted into the carbonaceous material during charging.

According to yet another aspect of the present invention, the present invention provides a method of forming the lithium battery assembly described in the first aspect, the method comprising a primary lithium/oxyhalide battery and a rechargeable secondary lithium battery with a capacity calculated according to application requirements Ion batteries are connected in parallel, and according to the selected primary lithium/oxyhalide battery type, the open circuit voltage of the rechargeable secondary lithium-ion battery in the full state is selected to be higher than the open circuit voltage of the parallel primary lithium/oxyhalide battery, so that the two The voltage of the rechargeable secondary lithium-ion battery under the condition of parallel connection and open circuit of the load terminal is lower than the voltage under the full state.

As a further improved embodiment of the present invention, the above-mentioned method also includes adjusting the ratio of the cathode material and the anode composite carbonaceous material in the rechargeable secondary lithium ion battery, so that the above-mentioned cathode material reversibly combines the capacity of lithium ions with the above-mentioned anode composite carbon The ratio of the capacity of the host material to reversibly bind lithium ions in the form of _LiC6 is between 0.5:1 and 2:1.

In the lithium battery assembly provided by the embodiments of the present invention, since the open circuit voltage of the rechargeable secondary lithium ion battery is higher than the open circuit voltage of the parallel primary lithium/oxyhalide battery, the two are connected in parallel and the load terminal is open circuit condition The voltage of the rechargeable secondary lithium-ion battery is lower than the voltage of the full state, thereby reducing the self-discharge phenomenon caused by aging and side reactions.

Furthermore, in a further improved embodiment, since the ratio of the capacity of the cathode material to reversibly bind lithium ions to the capacity of the anode composite carbonaceous material to reversibly bind lithium ions in the form of LiC is between 0.5: ₁ and 2:1, Thereby reducing the risk of lithium metal deposition on the surface of the carbonaceous material to form dendrites and side reactions when lithium ions are inserted into the carbonaceous material during charging.

Description of drawings

Fig. 1 is a schematic diagram of a circuit design described in the prior art, including a combination of primary batteries and capacitors connected in parallel;

Fig. 2 is a schematic diagram of circuit design of a lithium battery assembly according to an embodiment of the present invention, including a primary electrochemical cell and a secondary rechargeable lithium ion battery connected in parallel therewith;

3 is a schematic cross-sectional view of an electrode stack of a rechargeable secondary lithium ion battery in a lithium battery assembly according to an embodiment of the present invention;

Fig. 4 is in one embodiment of the present invention, the charging and discharging voltage and capacity relation curve of rechargeable secondary lithium-ion battery;

Fig. 5 is a voltage and time curve of a rechargeable secondary lithium-ion battery discharged at a rate of 7C at a temperature of -40°C in an embodiment of the present invention, and is compared with a commercial lithium-ion battery of the same capacity under the same conditions;

Fig. 6 shows that in one embodiment of the present invention, at the temperature of -40°C-85°C, the rechargeable secondary lithium-ion battery of the present invention is independently discharged with a graph of 350mA discharge current; and

Fig. 7 is a graph showing the pulse discharge data of the battery assembly formed by the parallel connection of the primary battery and the secondary battery of the present invention at a temperature of -40°C to 85°C in one embodiment of the present invention.

detailed description

Embodiments or examples of the present invention will be described in further detail below in conjunction with the accompanying drawings in order to explain the principle of the present invention. These embodiments or examples are described below in sufficient detail to enable those skilled in the art to practice the invention, however, it is to be understood that other embodiments may be utilized and changes may be made without departing from the spirit of the invention.

In the present invention, the term "wide temperature range" is a relative concept, and particularly refers to a wide range of operating temperatures of batteries in the prior art. For example, the rechargeable secondary lithium ion battery of the present invention can be used in a wide range of -40°C to 85°C, while the primary battery of the present invention can be used in a temperature range of -60°C to 85°C.

According to the rechargeable secondary lithium ion battery of the present invention, it comprises cathode material, anode material, diaphragm and electrolytic solution, wherein, described anode material is anode composite material, and in the described rechargeable secondary lithium ion battery The ratio of the capacity of the cathode material to reversibly bind lithium ions to the capacity of the anode composite carbonaceous material to reversibly bind lithium ions in the form of LiC ₆ is between 0.5:1 and 2:1.

Specifically, the anode composite material includes a composite carbonaceous material, the composite carbonaceous material includes a basic carbonaceous material and a microstructured carbonaceous material, and the basic carbonaceous material is selected from graphite, coke, carbon black, hard carbon, Soft carbon and combinations thereof, wherein the microstructured carbonaceous material is selected from graphene, graphene microflakes, single-layer carbon nanotubes, multilayer carbon nanotubes, mesophase microsphere carbon, microporous activated carbon and combinations thereof.

In one embodiment, the particle size of the basic carbonaceous material is between 0.5-100 microns. Preferably, the particle size of the basic carbonaceous material is between 0.8-50 microns. The corresponding microstructure scale of the microstructured carbonaceous material is less than 2 micrometers; preferably, the corresponding microstructure scale of the microstructured carbonaceous material is less than 500 nanometers.

Further, the mass proportion of the microstructured carbonaceous material in the composite carbonaceous material is between 0.5% and 50%, preferably, the mass of the microstructured carbonaceous material in the composite carbonaceous material The proportion is between 3-50%.

In the rechargeable secondary lithium ion battery of the present invention, the anode material in the rechargeable secondary lithium ion battery also includes a binder and a conductive agent, and the binder and the conductive agent are relative to the total mass of the anode material accounted for less than 30%. Preferably, the binder and the conductive agent account for less than 10% of the total mass of the anode material.

The cathode material in the rechargeable secondary lithium ion battery comprises a lithiated transition metal intercalation material selected from the group consisting of lithiated transition metal oxides, mixed lithiated transition metal salts and lithiated metal phosphoric acid One or more salts. In one embodiment, the lithiated transition metal intercalation material is selected from LiCoO ₂ , LiNix Co _{1-x O 2} , LiNi _x Al _{1- x} O ₂ , LiMn _x Ni _y Co _z O ₂ , _LiNix Co _yAlzO2 , _LiMnO2 , _LiFePO4 and _{combinations thereof} , more _{preferably LiMnO2} , _{LiNixCoyAlzO2 , LiNixCo1 - xO2 , LiMnxNiyCozO2 and combinations thereof} . Moreover, in the lithiated transition metal intercalation material, the molar ratio of Co in transition metal elements is lower than 25%.

The rechargeable secondary lithium ion battery includes a separator in contact with and impregnated with an electrolyte solution comprising at least one relatively low-viscosity solvent and at least one having a relatively low viscosity. A solvent with a high dielectric constant or a low melting point and a high boiling point, the relatively low viscosity solvent is selected from tetrahydrofuran, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, dipropyl carbonate, dipropyl carbonate, Ethylene glycol dimethyl ether, ethylene glycol dimethyl ether, the solvent with a relatively high dielectric constant or with a low melting point and a high boiling point is selected from ethyl carbonate, methyl acetate, methyl propionate, methyl bromide, methyl formate esters, ethyl acetate, ethyl propionate, ethyl bromide, propylene carbonate, butanediol carbonate, acetonitrile, dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone and mixtures thereof. Further, the electrolyte contains at least one additive that protects the electrode surface during circulation, and the additive is selected from one or more of vinylene carbonate, diethylstilbestrol, butane sultone, and dimethyl sulfide. kind. In addition, the electrolyte solution contains at least one lithium metal salt selected from LiPF ₆ , LiBF ₄ , LiBOB, LiTFSI, LiClO ₄ and combinations thereof. In one embodiment, the electrolyte solution includes a mixed solvent system of ethyl carbonate: dimethyl carbonate: ethyl methyl carbonate: diethyl carbonate: propyl acetate, and contains lithium metal salt and additives dissolved therein. Further, the molar ratio ranges of each solvent in the total mixed solvent system in the mixed solvent system are ethyl carbonate: 5% to 55%, ethyl methyl carbonate: 1% to 55%, diethyl carbonate: 3% to 50% %, dimethyl carbonate: 5% to 70%, propyl acetate: 5% to 60%. Preferably, the molar ratio of the additive to the mixed solvent system ranges from 5% to 75%, such as 5%, 15%, 30%, 50% or 75%.

The rechargeable secondary lithium ion battery of the present invention can work in a wide temperature range, that is, the battery can complete charging and discharging actions in a relatively wide temperature range. For example, the rechargeable secondary lithium ion battery of the present invention can realize charging and discharging functions in the temperature range of -40°C-85°C. Compared with the prior art, the rechargeable secondary lithium ion battery of the present invention greatly improves the problem that the rechargeable secondary lithium ion battery in the prior art cannot work normally in a low temperature environment, and realizes normal charging at extreme low temperature and extreme high temperature and discharge.

The structure and performance of the battery pack in which the primary battery and the secondary battery are connected in parallel according to the present invention will be described below with reference to the accompanying drawings.

First referring to Fig. 2, this figure is the circuit design of the lithium battery assembly according to an embodiment of the present invention, comprises primary lithium/oxyhalide battery 2 and rechargeable secondary lithium-ion battery 7, wherein primary battery 2 and secondary battery 7 Parallel connection via conductive connection. When a load is connected between the access terminals 8 and 9 and the circuit 6 is required to provide a large current, part of the current can be output by the secondary battery 7 so as to reduce the current demand for the primary battery 2 . The typical feature of this lithium battery assembly is that the open circuit voltage of the rechargeable secondary lithium ion battery 7 in a fully charged state is higher than that of the parallel connected primary lithium/oxyhalide battery 2, so that the two are connected in parallel and the load terminal is open. The voltage of the rechargeable secondary lithium-ion battery 7 is lower than the voltage of the fully charged state to reduce self-discharge caused by aging and side reactions. The so-called "the open circuit voltage of the rechargeable secondary lithium-ion battery 7 is higher than the open circuit voltage of the primary lithium/oxyhalide battery 2 in parallel" means that it is slightly higher, for example, with the primary lithium/oxyhalide battery The open circuit voltage is the calculation basis, and the open circuit voltage of the rechargeable secondary lithium-ion battery in a full state can be higher than the open circuit voltage of the primary lithium/oxyhalide battery, for example, 10% or less, preferably 5% or less, more preferably 2% higher than the open circuit voltage of the primary lithium/oxyhalide battery. % or less, most preferably less than 1% higher. If calculated by the absolute amount higher than the open circuit voltage of the primary lithium/oxyhalide battery, the open circuit voltage of the rechargeable secondary lithium-ion battery in the full state can be higher than the open circuit voltage of the primary lithium/oxyhalide battery, for example, 0.3V or less , preferably higher than 0.1V, more preferably higher than 0.05V, most preferably higher than 0.02V, for example higher than 0.01V.

It should be noted that FIG. 2 shows an embodiment with only one primary lithium/oxyhalide battery. In other embodiments, in order to meet different application requirements and the capacity of battery components needs to be increased, multiple primary lithium/oxyhalide batteries can be connected in parallel.

On the basis of the embodiment shown in Figure 2, the inventors have further studied and found that adjusting the ratio of the capacity of the cathode material to reversibly combine lithium ions to the capacity of the anode material to reversibly combine lithium ions is important for further improving the rechargeable secondary lithium ion battery. performance, thereby improving the overall performance of the above-mentioned lithium battery components is helpful. Specifically, a rechargeable secondary lithium-ion battery includes a cathode material and an anode composite carbonaceous material, wherein the ratio of the capacity of the cathode material to reversibly bind lithium ions to the capacity of the anode composite carbonaceous material to reversibly bind lithium ions in the form of LiC ₆ Between 0.5:1 and 2:1, this reduces the risk of deposition of lithium metal on the surface of the carbonaceous material to form dendrites and side reactions when lithium ions are inserted into the carbonaceous material during charging.

In one embodiment of the present invention, the primary lithium/oxyhalide battery can generally (but not limitedly) be a lithium/thionyl chloride battery or a lithium/sulfuryl chloride battery; especially a lithium/thionyl chloride battery with an operating voltage of 3.67V. Thionyl chloride battery or lithium/sulfuryl chloride battery with a working voltage of 3.9V.

Referring now to FIG. 3, this figure is a schematic cross-sectional view of an electrode stack of a rechargeable secondary lithium ion battery in a lithium battery assembly according to an embodiment of the present invention.

FIG. 3 illustrates a portion of the secondary battery 7 that can be used in FIG. 2 . The rechargeable secondary lithium ion battery part includes an anode 15 , a cathode 16 and a separator 12 . The anode 15 may include an anode conductive support 11, which may be selected from conductive polymers, carbon, aluminum, copper, nickel, stainless steel, chromium, gold and combinations thereof. The thickness of the anode conductive support 11 is preferably 5-100 microns, more preferably 10-20 microns, but not limited to other thickness values. The anode conductive support 11 is coated, preferably on both sides, with an anode active material 10 mainly composed of composite carbonaceous material. The anode active material 10 may also contain a binder and a conductive agent in addition to the composite carbonaceous material, but the total mass ratio of the binder and the conductive agent to the anode material is less than 30%, for example, the binder and the conductive agent are relative to the anode The total mass proportion of materials can be 25%, 20%, 15%, 10%, 5% or 2%. Preferably it is less than or equal to 20%, such as 15% or 10%. Binders and conductive agents are non-battery active materials, which play an auxiliary (film-forming and auxiliary conductive) role in electrode materials. Excessive mass ratio of binder and conductive agent will lead to relative reduction of effective active materials and affect battery capacity. The adhesive and conductive agent of the present invention can fully play an auxiliary role under the above-mentioned mass ratio, and will not affect the battery capacity. The composite carbonaceous material is composed of at least two materials, including basic carbonaceous materials and microstructured carbonaceous materials. The basic carbonaceous material is the main active anode material of a conventional lithium-ion battery, and its advantages lie in relatively high lithium ion intercalation specific capacity (ie, capacity density) and relatively low material cost. Microstructured carbonaceous materials are also used in lithium-ion battery electrode materials, and their specific working mechanisms are different under different conditions. In the present invention, a non-embedded lithium storage mechanism is provided, thereby improving the rate capability of the charging and discharging process. In the present invention, the composite carbonaceous material comprising the above two materials can be used to obtain the balanced performance required by the application of the invention in terms of the required high-current discharge performance and capacity. The basic carbonaceous material can be selected generally but not limitedly from graphite, coke, carbon black, hard carbon, soft carbon and combinations thereof, and the microstructured carbonaceous material can be selected generally but not limitedly from graphene ( Graphene), graphene microplatelet (Graphene nanoplatelet), single wall carbon nanotube (SWCNT), multilayer carbon nanotube (MWCNT), mesophase microsphere carbon (MCMB), microporous activated carbon and combinations thereof. The particle size of the basic carbonaceous material is between 0.5-100 microns, such as 0.5 microns, 0.8 microns, 10 microns, 50 microns or 80 microns. Preferably, it is between 0.8-80 microns, such as 1 micron, 5 microns, 20 microns or 50 microns. More preferably, it is between 0.8-50 microns, such as 1 micron or 10 microns. The particles within the above range can achieve a better balance in terms of compaction density, film-forming performance and lithium ion diffusion depth. The corresponding microstructure scale (such as thickness, diameter or void, etc.) of the microstructure carbonaceous material is less than 2 microns, preferably less than 500 nanometers, the lower the microstructure scale, the larger the specific surface area, the better the lithium storage capacity and rapid discharge capacity . The mass ratio of microstructured carbonaceous materials in composite carbonaceous materials can achieve excellent results between 0.5% and 50%, because the microstructured carbonaceous materials are lower than the basic carbonaceous materials, which will not increase the specific capacity of the battery too much. significantly lower. Generally, the mass proportion of the microstructured carbonaceous material in the composite carbonaceous material can be between 0.5% and 50%, or between 3% and 50%.

Cathode 16 includes a cathode conductive support 14, which may be a material selected from the group consisting of conductive polymers, carbon, aluminum, copper, nickel, stainless steel, chromium, gold, and combinations thereof. The thickness of the cathode conductive support 14 is preferably 5-100 microns, more preferably 10-20 microns, but not limited to other thickness values. The cathode conductive support 14 is coated, preferably on both sides, with a cathode active material 13 consisting essentially of a lithiated transition metal intercalation material. Wherein the lithiated transition metal intercalation material can be generally but not limited to one or more selected from lithiated transition metal oxides, mixed lithiated transition metal salts and lithiated metal phosphates, preferably LiCoO ₂ , _LiNix Co _1-x O ₂ , LiNi _x Al _1-x O ₂ , LiMn _x Ni _y Co _z O ₂ , LiNi _x Co _y Al _z O ₂ , LiMnO ₂ , LiFePO ₄ and combinations thereof, more preferably LiMnO ₂ , LiNi _x Co _y Al _z O ₂ , LiNi _x Co _1-x O ₂ , LiMn _x Ni _y Co _z O ₂ , and combinations thereof. The substances represented by these chemical formulas have general concepts in the field, wherein x, y and z in each chemical formula have general values in the field, and these values are known in the art. Even so, in some preferred embodiments of the present invention, the value of the subscript of Mn is 0.3～0.9, the value of the subscript of Ni is 0.3～0.9, and the value of Al is under the situation of independent subscript (non-correlation value) In the range of 0.05 to 0.3, the value of Co is limited between 0.05 and 0.25. It should be understood that the value ranges given here are only exemplary, and should not be construed as limitations on general values in this field.

In one embodiment, in the lithiated transition metal intercalation material, the molar ratio of Co in transition metal elements is lower than 25%, such as 20%, 15%, 10% or 5%.

The separator 12 is a separator material for separating the cathode from the anode, and the electrolyte can impregnate the separator. Such a membrane material may be any suitable porous non-conductive material, such as, but not limited to, a polypropylene film with a microporous structure, or any other suitable membrane material.

A rechargeable secondary lithium ion battery comprising an electrolyte in contact with an anode material and a cathode material and impregnating a separator, the electrolyte comprising at least one relatively low viscosity solvent and at least one solvent having a relatively high dielectric constant or having a low melting point and a high Solvents with boiling point, among them, low viscosity solvents ensure ion transport performance under different conditions; high dielectric constant solvents ensure low leakage rate; low melting point and high boiling point solvents ensure the stability of batteries under high and low temperature conditions. Relatively low-viscosity solvents may be selected from tetrahydrofuran (THF), dimethylcarbonate (DMC), diethylcarbonate (DEC), methylethylcarbonate (ethylmethylcarbonate/EMC), typically but not limitedly. ), methyl propyl carbonate (methyl propyl carbonate/MC), dipropyl carbonate (dipropylcarbonate), diethylene glycol dimethyl ether (diglyme), ethylene glycol dimethyl ether (1,2dimethoxyethane) and their combinations; with relative A solvent with a high dielectric constant or with a low melting point and a high boiling point may be selected generally but not limitedly from ethylene carbonate (EC), methyl acetate (methyl acetate), methyl propanoate (methyl propanoate/MP) , methyl bromide (MB), methyl formate (methyl formate/MF), ethyl acetate (ethylacetate/EA), propyl acetate (propyl acetate/PA), ethyl propanoate (ethyl propanoate/EP), bromine Ethane (ethyl bromide), propylene carbonate (propylene carbonate), butylene carbonate (butylenecarbonate), acetonitrile (acetonitrile), dimethyl sulfoxide (dimethyl sulfoxide), dimethylformamide (Dimethylformamide), N- N-methyl-pyrrolidone (NMP) and combinations thereof. In addition, the above-mentioned rechargeable secondary lithium-ion battery electrolyte contains at least one additive that protects the electrode surface during cycling, and the additive is usually but not limited to vinylene carbonate (vinylene carbonate), diethylstilbestrol One or more of (diethylstilbestrol), butanesultone (Butanesultone), dimethyl sulfide (dimethyl sulfide). In addition, the above-mentioned rechargeable secondary lithium ion battery electrolyte contains at least one lithium metal salt, and the lithium metal salt can be selected from LiPF ₆ , LiBF ₄ , LiBOB, LiTFSI, LiClO ₄ and combinations thereof generally but not limitedly.

In one embodiment of the present invention, the rechargeable secondary lithium-ion battery electrolyte combination includes a mixed solvent system of EC:DMC:EMC:DEC:PA, and contains lithium metal salt and additives dissolved therein. Preferably, the molar ratio range of each solvent in the total mixed solvent system in the mixed solvent system is EC: 5%-55%, EMC: 1%-55%, DEC: 3%-50%, DMC: 5% %-70%, PA: 5%-60%; preferably, the molar ratio range of the additive to the mixed solvent system is 5%-75%. Such a system has the function of balancing the solubility of lithium salt, ion conductivity and stability under high and low temperature working conditions.

The implementation of the present invention and its beneficial effects will be described in detail below through specific examples. It should be understood that these examples do not constitute a limitation to the protection scope of the present invention, and the protection scope of the present invention is based on the claims.

Example 1

In order to demonstrate the superior performance of the embodiment of the present invention, a rechargeable secondary lithium-ion battery was constructed according to the scheme involved in the present invention, and relevant basic tests were carried out.

A pouch type test battery was fabricated using the following components. The anode is made of 9-micron copper foil, and a carbon-based anode: carbon powder: PVDF (80:10:10w%) hard material mixture layer is coated on both sides of the copper foil with a thickness of 27.5 microns (each side). The carbon-based anode material particles are flakes with a thickness of 100-200 nanometers and a diameter of 500 nanometers to 5 micrometers, the total thickness of the anode is 64 micrometers, the width of the anode is 22 millimeters, and the length of the anode is 1185 millimeters. Herein, "w%" all represent mass percent.

The cathode selects 20 micron aluminum foil as the carrier, and the cathode material with a thickness of 24 microns is coated on both sides of the aluminum foil, which is made of a mixture of LiAlNiCoO2, carbon powder and PVDF (respectively 80%, 10% and 10% by weight) become. The cathode has a total thickness of 68 microns, a width of 18 mm and a length of 1125 mm. Carbon powder in the anode and cathode mix is used to improve conductivity, while PVDF is used as a binder.

The battery uses a 25-micron thick Celgard-type film to separate the cathode and anode, and the film is a three-layer composite film of PP-PE-PP. The electrolyte is a mixture of EC: EMC: DEC: DMC: PA (17.88: 0.49: 19.96: 17.15: 44.53w%), and the lithium salt is LiPF6 with a concentration of 1 mole/liter. The stack of batteries (comprising anode, cathode and separator added between them) is assembled according to the spiral winding configuration as known in the art, puts into aluminum plastic film afterwards, pours liquid in dry environment after drying, then Vacuum packaging and activation. The battery is charged and discharged with a current of 1C within the voltage range of 2.75-3.67V, and its measured capacity is about 45mAh.

Example 2

Lithium-ion batteries were manufactured using the processes and materials described in Example 1 above, wherein the anode material used was a spherical carbon-based anode material, and the particle size of the spherical carbon-based anode material was 1 micron to 10 microns. The battery prepared in this embodiment is charged and discharged with a current of 1C in the voltage range of 2.75-3.76, and the measured capacity is about 35mAh.

Example 3

The flow process and materials described in the above-mentioned embodiment 1 are used to manufacture lithium-ion batteries, wherein the anode material uses a sheet-like carbon-based material, and the particle thickness of the sheet-like carbon-based material is 500 nanometers to 21 microns, and the diameter is 30 microns to 100 microns. The battery is charged and discharged with a current of 1C within the voltage range of 2.75-3.76, and its measured capacity is about 47mAh.

Example 4

Lithium-ion batteries were manufactured using the processes and materials described in Example 1 above, wherein the anode material used was spherical carbon-based materials, and the diameter of the spherical carbon-based materials was 5 microns to 20 microns. The battery is charged and discharged with a current of 1C within the voltage range of 2.75-3.76, and its measured capacity is about 43mAh.

Example 5

Lithium-ion batteries were manufactured using the processes and materials described in Example 1 above, wherein the ratio of microstructured carbonaceous material: PVDF: carbon-based anode material was 0.5:1:98.5. The battery is charged and discharged with a current of 1C in the voltage range of 2.75-3.76, and its measured capacity is about 53mAh.

Example 6

Lithium-ion batteries were manufactured using the processes and materials described in Example 1 above, wherein the ratio of microstructured carbonaceous material: PVDF: carbon-based anode material was 50:10:40. Among them, the microstructure carbonaceous material is a mixture of Super-P and activated carbon. The battery is charged and discharged with a current of 1C in the voltage range of 2.75-3.76. The measured capacity is about 18mAh.

Figure 4 demonstrates the charge and discharge characteristics of a battery in one embodiment of the present invention. It shows that the voltage of the rechargeable secondary lithium-ion battery is about 3.68V in a fully charged state, and the capacity value is about 43 milliampere hours (mAh). Its open circuit voltage is slightly higher than the open circuit voltage of the commonly used primary lithium/thionyl chloride (Li/SOCl2) battery (3.67V) in the fully charged state, so the capacity of the secondary battery can be utilized as much as possible in the parallel state. At the same time, it also reduces the leakage phenomenon in the over-charged state.

FIG. 5 shows the transient discharge characteristics of the rechargeable secondary lithium-ion battery constructed in one embodiment of the present invention under the condition of low temperature and high current. In one embodiment, the discharge condition is to discharge at a rate of 7C (300mA) in an environment of -40°C under a fully charged state. The general commercial battery with the same capacity was used as an experiment under the same conditions as a comparison. As can be seen in Figure 5, the battery produced according to the solution of the present invention is discharged at a high current of 300mA under low temperature conditions, and the output voltage can still be maintained at about 2.8V within 2 seconds, which is higher than the minimum voltage required by common communication electronic devices ( Such as 2.5V). However, compared with commercial lithium-ion batteries, the voltage drops sharply to 1.5V and below within a discharge time of less than 0.5 seconds, losing the ability to continue to supply power to related equipment.

Figure 6 shows that in one embodiment of the present invention, the discharge current of the rechargeable secondary lithium ion battery of the present invention is at the temperatures of -40°C, -25°C, 20°C and 85°C within 10 seconds. The voltage versus time curve for 350mA. As can be seen from the figure, under extreme low temperature conditions (-40°C), the rechargeable secondary lithium-ion battery of the present invention still has good discharge performance, and can maintain a voltage above 2V under the condition of a large current discharge close to 9C, and can Satisfies the use of most electronic devices at low temperatures, and can be recharged at this temperature (-40°C). Along with the rising of experiment temperature, the discharge situation of rechargeable secondary lithium ion battery of the present invention all maintains at higher working voltage in the discharge time of 10 seconds of whole test, especially under high temperature (85 ℃) can It maintains almost the same discharge performance as at normal temperature, and it is also possible to recharge at this temperature (85°C).

Figure 7 shows that in one embodiment of the present invention, the battery assembly formed by the parallel connection of the primary battery and the rechargeable secondary lithium-ion battery of the present invention is under the temperature conditions of -40°C, 25°C and 85°C. Pulse discharge data Graph. Compared with a single rechargeable secondary lithium ion battery, the battery assembly of the present invention also has better discharge performance in the low temperature range. That is, in the case of charging and discharging for the same number of times (such as 10 times), the discharge performance curve in the above-mentioned wide temperature range is relatively stable, which greatly improves the performance of the entire battery assembly. It can be seen that the battery of the present invention fundamentally solves the problem that primary batteries and rechargeable secondary lithium-ion batteries cannot be used in extreme low temperature and extreme high temperature harsh environments, and is conducive to improving and promoting the development of the entire battery industry. develop.

In addition, in order to increase the voltage or power of the battery pack, different series and/or parallel combinations of the primary battery and the rechargeable secondary lithium-ion battery of the present invention can also be performed. For example, connecting a plurality of rechargeable secondary lithium-ion batteries in series and then connecting a primary battery in parallel, or connecting a plurality of rechargeable secondary lithium-ion batteries in series and then connecting a plurality of primary batteries in series in parallel, etc., these can be used in practice Select and combine as desired. It is worth mentioning that the battery packs of different combinations mentioned above can be charged, discharged and used normally in the range of the above extreme low temperature (-40°C) and extreme high temperature (85°C), and there will be no problems such as flammable and explosive Risk happens.

The above content is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be assumed that the specific implementation of the present invention is limited to these descriptions. Those of ordinary skill in the technical field to which the present invention belongs can also make some simple deduction or replacement without departing from the concept of the present invention. It should be understood that all these derivations or substitutions are within the protection scope of the claims of the present invention.

Claims (32)

1. Rechargeable secondary lithium-ion battery, comprising cathode material, anode material, diaphragm and electrolyte; It is characterized in that, described anode material is anode composite material, and all in described rechargeable secondary lithium-ion battery The ratio of the capacity of the cathode material to reversibly bind lithium ions to the capacity of the anode composite carbonaceous material to reversibly bind lithium ions in the form of LiC ₆ is between 0.5:1 and 2:1. 2. rechargeable secondary lithium ion battery according to claim 1, is characterized in that, described anode composite material comprises composite carbonaceous material, and this composite carbonaceous material comprises basic carbonaceous material and microstructure carbonaceous material, so The basic carbonaceous material is selected from graphite, coke, carbon black, hard carbon, soft carbon and combinations thereof, and the microstructured carbonaceous material is selected from graphene, graphene microsheets, single-layer carbon nanotubes, multilayer carbon nanotubes Tubes, mesophase microspheroidal carbons, microporous activated carbons, and combinations thereof. 3. The rechargeable secondary lithium ion battery according to claim 2, characterized in that, the particle size of the basic carbonaceous material is between 0.5-100 microns, preferably, the particle size of the basic carbonaceous material Between 0.8-50 microns. 4. The rechargeable secondary lithium ion battery according to claim 3, characterized in that, the corresponding microstructure scale of the microstructured carbonaceous material is less than 2 microns; preferably, the corresponding microstructure of the microstructured carbonaceous material The structural scale is less than 500 nanometers. 5. The rechargeable secondary lithium-ion battery according to claim 2, characterized in that, the mass ratio of the microstructure carbonaceous material in the composite carbonaceous material is 0.5%-50% Between, preferably, the mass proportion of the microstructure carbonaceous material in the composite carbonaceous material is between 3-50%. 6. according to the rechargeable secondary lithium ion battery described in any one of claim 2-5, it is characterized in that, in the described rechargeable secondary lithium ion battery, anode material also comprises binding agent and conductive agent, and described bonding The proportion of the total mass of the binder and the conductive agent to the anode material is less than 30%, preferably, the binder and the conductive agent account for less than 10% of the total mass of the anode material. 7. The rechargeable secondary lithium-ion battery according to claim 1, wherein the cathode material in the rechargeable secondary lithium-ion battery comprises a lithiated transition metal intercalation material, and the lithiated transition metal intercalation material One or more selected from lithiated transition metal oxides, mixed lithiated transition metal salts and lithiated metal phosphates. 8. The rechargeable secondary lithium-ion battery according to claim 7, wherein the lithiated transition metal intercalation material is selected from the group consisting of LiCoO ₂ , LiNi _x Co _1-x O ₂ , LiNi _x Al _{1-x O2} , _{LiMnxNiyCozO2 , LiNixCoyAlzO2 , LiMnO2} , _LiFePO4 and _{combinations thereof} , _{more preferably LiMnO2 , LiNixCoyAlzO2 , LiNixCo1 - x} O ₂ , LiMn _x Ni _y Co _z O ₂ and combinations thereof. 9. The rechargeable secondary lithium ion battery according to claim 7 or 8, characterized in that, in the lithiated transition metal intercalation material, the molar ratio of Co in transition metal elements is lower than 25%. 10. The rechargeable secondary lithium-ion battery according to claim 1, wherein the electrolyte in the rechargeable secondary lithium-ion battery is in contact with the anode material and the cathode material and impregnates the diaphragm, wherein, The electrolytic solution comprises at least one relatively low-viscosity solvent and at least one solvent with a relatively high dielectric constant or a low melting point and a high boiling point, and the relatively low-viscosity solvent is selected from tetrahydrofuran, dimethyl carbonate, dicarbonate Ethyl ester, ethyl methyl carbonate, methyl propyl carbonate, dipropyl carbonate, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, said solvents with relatively high dielectric constant or with low melting point and high boiling point Ethyl carbonate, methyl acetate, methyl propionate, methyl bromide, methyl formate, ethyl acetate, ethyl propionate, ethyl bromide, propylene carbonate, butylene carbonate, acetonitrile, dimethylmethylene Sulfone, dimethylformamide, N-methylpyrrolidone and mixtures thereof. 11. The rechargeable secondary lithium-ion battery according to claim 10, characterized in that, the electrolyte contains at least one additive that protects the electrode surface during circulation, and the additive is selected from vinylene carbonate , diethylstilbestrol, butane sultone, and one or more of dimethyl sulfide. 12. The rechargeable secondary lithium-ion battery according to claim 10 or 11, wherein the electrolyte contains at least one lithium metal salt selected from LiPF ₆ , LiBF ₄ , LiBOB , LiTFSI, LiClO ₄ and combinations thereof. 13. The rechargeable secondary lithium ion battery according to claim 10 or 11, wherein the electrolyte comprises ethyl carbonate: dimethyl carbonate: ethyl methyl carbonate: diethyl carbonate: propyl acetate A mixed solvent system containing lithium metal salt and additives dissolved therein. 14. The rechargeable secondary lithium ion battery according to claim 13, characterized in that, the molar ratio ranges of each solvent in the total mixed solvent system in the mixed solvent system are ethyl carbonate: 5% to 55%, Ethyl methyl carbonate: 1% to 55%, diethyl carbonate: 3% to 50%, dimethyl carbonate: 5% to 70%, propyl acetate: 5% to 60%; Preferably, the molar ratio of the additive to the mixed solvent system ranges from 5% to 75%. 15. A lithium battery assembly capable of providing high discharge pulses in a wide temperature range, characterized in that the lithium battery assembly includes: Primary lithium/oxyhalide batteries; and A rechargeable secondary lithium ion battery, which is connected in parallel with the primary lithium/oxyhalide battery, wherein the rechargeable secondary lithium ion battery contains a cathode material and an anode composite carbonaceous material, and the cathode material reversibly The ratio of the capacity to bind lithium ions to the capacity of the anode composite carbonaceous material to reversibly bind lithium ions in the form of LiC is between 0.5: ₁ and 2:1; Moreover, the open circuit voltage of the rechargeable secondary lithium ion battery in a fully charged state is higher than the open circuit voltage of the parallel connected primary lithium/oxyhalide battery. 16. The lithium battery assembly according to claim 15, wherein the anode material in the rechargeable secondary lithium ion battery comprises a composite carbonaceous material, and the composite carbonaceous material comprises a basic carbonaceous material and a microstructured carbonaceous material, the basic carbonaceous material is selected from graphite, coke, carbon black, hard carbon, soft carbon and combinations thereof, and the microstructured carbonaceous material is selected from graphene, graphene microsheets, single-layer carbon nanotubes, multilayer carbonaceous Layered carbon nanotubes, mesophase microspheroidal carbons, microporous activated carbons and combinations thereof. 17. The lithium battery assembly according to claim 16, wherein the particle size of the basic carbonaceous material is between 0.5-100 microns, preferably, the particle size of the basic carbonaceous material is 0.8-50 microns between microns. 18. The lithium battery assembly according to claim 16, wherein the corresponding microstructure scale of the microstructured carbonaceous material is less than 2 microns; preferably, the corresponding microstructure scale of the microstructured carbonaceous material is less than 500 μm. Nano. 19. The lithium battery assembly according to any one of claims 16-18, wherein the mass proportion of the microstructured carbonaceous material in the composite carbonaceous material is between 0.5% and 50%; preferably Specifically, the mass proportion of the microstructured carbonaceous material in the composite carbonaceous material is between 3-50%. 20. The lithium battery assembly according to any one of claims 16-18, wherein the anode material in the rechargeable secondary lithium ion battery also includes a binder and a conductive agent, and the binder and the conductive agent The proportion of the total mass of the anode material is less than 30%, preferably, the binder and the conductive agent account for less than 10% of the total mass of the anode material. 21. The lithium battery assembly according to claim 15, wherein the cathode material in the rechargeable secondary lithium ion battery comprises a lithiated transition metal intercalation material selected from the group consisting of lithiated transition metal intercalation materials. One or more of transition metal oxides, mixed lithiated transition metal salts, and lithiated metal phosphates. 22. The lithium battery assembly according to claim 20, wherein the lithiated transition metal intercalation material is selected from LiCoO ₂ , LiNi _x Co _1-x O ₂ , LiNi _x Al _1-x O ₂ , LiMn _x Ni _y Co _z O ₂ , LiNi _x Co _y Al _z O ₂ , LiMnO ₂ , LiFePO ₄ and combinations thereof, more preferably LiMnO ₂ , LiNi _x Co _y Al _z O ₂ , LiNi _x Co _1-x O ₂ , LiMn _x Ni _y Co _z O ₂ and combinations thereof. 23. The lithium battery assembly according to claim 21 or 22, characterized in that, in the lithiated transition metal intercalation material, the molar ratio of Co in transition metal elements is lower than 25%. 24. The lithium battery assembly according to claim 15, wherein the rechargeable secondary lithium-ion battery comprises an electrolyte that is in contact with the anode material and the cathode material and impregnates the diaphragm, the electrolyte comprising at least one A relatively low viscosity solvent and at least one solvent with a relatively high dielectric constant or with a low melting point and a high boiling point, the relatively low viscosity solvent being selected from tetrahydrofuran, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, Methyl propyl carbonate, dipropyl carbonate, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, the solvent with a relatively high dielectric constant or with a low melting point and a high boiling point is selected from ethyl carbonate, methyl acetate ester, methyl propionate, methyl bromide, methyl formate, ethyl acetate, ethyl propionate, ethyl bromide, propylene carbonate, butylene carbonate, acetonitrile, dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone and mixtures thereof. 25. The lithium battery assembly according to claim 24, wherein the electrolyte contains at least one additive that protects the electrode surface during circulation, and the additive is selected from the group consisting of vinylene carbonate, diethylstilbestrol, butyl One or more of sultone and dimethyl sulfide. 26. The lithium battery assembly according to claim 24 or 25, wherein the electrolyte contains at least one lithium metal salt selected from LiPF ₆ , LiBF ₄ , LiBOB, LiTFSI, LiClO ₄ and combinations thereof. 27. The lithium battery assembly according to claim 24 or 25, wherein the electrolyte comprises a mixed solvent system of ethyl carbonate: dimethyl carbonate: ethyl methyl carbonate: diethyl carbonate: propyl acetate , and contains lithium metal salt and additives dissolved therein. 28. The lithium battery assembly according to claim 27, wherein the molar ratio range of each solvent in the mixed solvent system in the total mixed solvent system is ethyl carbonate: 5% to 55%, ethyl methyl carbonate : 1% ~ 55%, diethyl carbonate: 3% ~ 50%, dimethyl carbonate: 5% ~ 70%, propyl acetate: 5% ~ 60%; Preferably, the molar ratio of the additive to the mixed solvent system ranges from 5% to 75%. 29. The lithium battery assembly according to claim 15, wherein the primary battery comprises a lithium/thionyl chloride battery or a lithium/sulfuryl chloride battery as a primary lithium/oxyhalide battery; Preferably, a lithium/thionyl chloride battery with a working voltage of 3.67V or a lithium/thionyl chloride battery with a working voltage of 3.9V is selected as the primary lithium/oxyhalide battery. 30. A method for forming a lithium battery assembly capable of providing high discharge pulses in a wide temperature range, characterized in that the method comprises: Connect primary lithium/oxyhalide batteries and rechargeable secondary lithium-ion batteries in parallel with the capacity calculated according to the application requirements; Depending on the type of primary lithium/oxyhalide cell selected, the open circuit voltage of the rechargeable secondary lithium-ion battery at full charge is higher than that of primary lithium/oxyhalide cells connected in parallel; and The voltage of the rechargeable secondary lithium-ion battery is lower than the voltage of the full state when the two are connected in parallel and the load end is open. 31. The method according to claim 30, further comprising adjusting the ratio of the cathode material and the anode composite carbonaceous material in the rechargeable secondary lithium ion battery so that the cathode material reversibly binds lithium ions The ratio of the capacity of the anode composite carbonaceous material to the capacity of reversibly binding lithium ions in the form of LiC ₆ is between 0.5:1 and 2:1. 32. The method according to claim 30 or 31, further comprising selecting a lithium/thionyl chloride battery or a lithium/sulfuryl chloride battery as the primary lithium/oxyhalide battery; Preferably, a lithium/thionyl chloride battery with a working voltage of 3.67V or a lithium/thionyl chloride battery with a working voltage of 3.9V is selected as the primary lithium/oxyhalide battery.