CN112688004B - Cell type aerospace multifunctional structure lithium battery - Google Patents

Cell type aerospace multifunctional structure lithium battery Download PDF

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CN112688004B
CN112688004B CN202110269961.2A CN202110269961A CN112688004B CN 112688004 B CN112688004 B CN 112688004B CN 202110269961 A CN202110269961 A CN 202110269961A CN 112688004 B CN112688004 B CN 112688004B
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battery
rubber pad
silicone rubber
cover plate
grid
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CN112688004A (en
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朱仕尧
李东旭
吴军
范才智
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National University of Defense Technology
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Abstract

The invention discloses a cell type aerospace multifunctional structure lithium battery which comprises an external supporting structure used for providing bearing capacity, wherein the external supporting structure comprises an upper cover plate, a grid type frame and a lower cover plate which are of a sandwich structure, a grid type battery cabin is arranged in the grid type frame, and a plurality of single batteries used for realizing the function of a storage battery pack are arranged in the grid type battery cabin. The invention adopts an external supporting structure consisting of an upper cover plate, a grid type frame and a lower cover plate which are in a sandwich structure to provide bearing capacity, and a plurality of single batteries used for realizing the function of the storage battery pack are arranged in a grid type battery compartment and serve as basic units to realize the function of the storage battery pack, thereby realizing the functions of bearing, supplying and storing electricity, and being beneficial to realizing the miniaturization, integration and compactness of the structures of the spacecraft batteries including satellites and the cabin body.

Description

Cell type aerospace multifunctional structure lithium battery
Technical Field
The invention relates to a spacecraft power supply technology, in particular to a cell type aerospace multifunctional structure lithium battery.
Background
Space structures need to be designed to be as light as possible and small in size due to the limitation of emission resources. The multifunctional structure lithium battery integrates multiple functions of structure bearing, power supply, power storage and the like into a unified structure body, so that the redundant weight and volume of equipment can be greatly saved, the integral functional mass ratio and functional volume ratio are improved, and the design requirement of a spacecraft platform is met.
However, as disclosed in chinese patent application No. 201610307086.1, a multifunctional structure for electrical energy and mechanical environment management is disclosed, in which the conventional lithium battery is not integrated with the deck, and the single battery needs to be assembled into a battery pack having a protective case, and then the battery pack is assembled. The multistage assembly mode not only has higher design complexity, but also introduces redundant battery packs to protect the quality of the shell, so that the structural performance still has a space for improvement. For example, chinese patent application No. 201610303836.8 discloses a multifunctional bulkhead structure for a microsatellite system, which describes a multifunctional structural bulkhead, and directly embeds a battery pack into a space of the bulkhead in a shape of a Chinese character ri, but does not have a standardized basic pack unit, and has too much constraint on the embedded structure, so that the multifunctional structural bulkhead structure is only applicable to a microsatellite, does not have wide expansibility, and needs to systematically redesign the structural system, the circuit system, the electromagnetic compatibility, the negative pressure protection, the insulation, the ground protection, and the like of a structural lithium battery.
In general, lithium batteries of conventional construction suffer from the following disadvantages:
(1) structural system design aspect: firstly, the traditional structure lithium battery configuration adopts a battery-battery pack-structure battery multi-layer pack mode, so that more redundant quality is brought; secondly, the traditional structure lithium battery has strict requirements on the frame structure configuration, does not have good expansion capability and has limited application range; the assembling mode of each single battery in the lithium battery with the traditional structure is different, and the condition that each single battery has the same mechanical and heat conduction environment after being assembled cannot be ensured;
(2) design of circuit system: the traditional structure lithium battery only has a basic battery pack function, and the feedback of internal voltage and temperature change is not realized in the circuit design. Secondly, the spacecraft is in an on-orbit satellite state and cannot repair and replace batteries, the traditional structure lithium battery does not realize strict screening of single batteries, reject the unqualified and inconsistent single batteries and match and group the screened batteries. In the connection process of the battery pack set and the detection system of the lithium battery with the traditional structure, the circuit connection mode is not reasonably designed, so that the single-point failure in the circuit cannot be avoided, and the impedance balance of each branch of the circuit can be ensured.
(3) Electromagnetic compatibility design aspect: the traditional structure lithium battery does not carry out systematic consideration to the wiring mode of the strong current closed circuit, and when the area enclosed is large, additional electromagnetic torque is easily introduced, so that the overall torque balance relation of the satellite is damaged.
(4) Negative pressure protection design aspect: because a small amount of gas still exists in the battery, certain air pressure exists in the battery, and the air pressure is close to zero under the space environment, the internal air pressure is greater than the environmental pressure, and a negative pressure effect can be introduced to cause the battery to expand. And the aluminum-plastic film package on the outer layer of the solid soft package single battery does not have the expansion resistance. The traditional structure lithium battery usually carries out negative pressure protection on a carbon fiber protective shell additionally arranged outside a single battery, so that additional mass is introduced;
(5) the design aspect of the grounding protection is as follows: the short-circuit fault refers to that the short-time current of the battery pack is rapidly increased and the temperature is increased due to the lap joint of the anode and the cathode or the ground wire in the structural lithium battery, so that the function of the battery is lost, and even the leakage and explosion of the single battery are caused. The traditional structure lithium battery does not carry out circuit short circuit fault protection, and cannot ensure reliable insulation treatment of the single battery and the connecting accessories thereof.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: aiming at the problems in the prior art, the invention provides a cell type space multifunctional structure lithium battery, which adopts an external support structure consisting of an upper cover plate, a grid type frame and a lower cover plate which are in a sandwich structure to provide bearing capacity, and adopts a plurality of single batteries which are installed in a grid type battery cabin and used for realizing the function of a storage battery as basic units to realize the function of the storage battery, thereby realizing the functions of bearing, supplying and storing electricity, and being beneficial to realizing the miniaturization, integration and compactness of spacecraft batteries including satellites and cabin structures.
In order to solve the technical problems, the invention adopts the technical scheme that:
a cellular type aerospace multifunctional structure lithium battery comprises an external support structure for providing bearing capacity, the external supporting structure comprises an upper cover plate, a grid type frame and a lower cover plate which are of a sandwich structure, and a grid-type battery compartment is arranged in the grid-type frame, a plurality of single batteries for realizing the function of the storage battery pack are arranged in the grid-type battery compartment, an upper silicone rubber pad for insulation, heat conduction and vibration reduction is arranged between the single battery and the upper cover plate, a lower silicone rubber pad for insulation, heat conduction and vibration reduction is arranged between the single battery and the lower cover plate, a silicon rubber gasket is filled between the periphery of the single battery and the grid-type battery compartment, the upper silicon rubber gasket, the lower silicon rubber gasket and the silicon rubber gasket are wrapped outside the single battery to form a full-enclosure structure, the single battery, the upper silicon rubber pad, the lower silicon rubber pad and the filling silicon rubber pad form a single battery cell assembly.
Optionally, the total thickness of the single battery, the upper silicone rubber pad and the lower silicone rubber pad is greater than the height of the grid-type frame, so that the upper silicone rubber pad and the lower silicone rubber pad are in a pre-pressing state after installation, the single battery is respectively matched with the upper silicone rubber pad and the lower silicone rubber pad through friction force, the upper silicone rubber pad is matched with the upper cover plate through friction force, and the lower silicone rubber pad is matched with the lower cover plate through friction force.
Optionally, the thicknesses of the upper silicone rubber pad and the lower silicone rubber pad satisfy constraint conditions:
Figure 840764DEST_PATH_IMAGE001
in the above formula, the first and second carbon atoms are,h s the thickness of the upper silicone rubber pad is the same as that of the lower silicone rubber pad,h x the thickness of the lower silicone rubber pad is the same,h k is the structural height of the single battery installation cavity,h d is the thickness of the unit cell,p d is the internal gas pressure of the battery of the unit cell,A d is the vertical projection area of the single battery,E j is the elastic modulus of the silicon rubber materials of the upper silicon rubber pad and the lower silicon rubber pad,A j the vertical projection areas of the upper silicone rubber pad and the lower silicone rubber pad are provided.
Optionally, the thicknesses of the upper silicone rubber pad and the lower silicone rubber pad are equal, the sizes of the upper silicone rubber pad and the lower silicone rubber pad are the same, and the thicknesses of the upper silicone rubber pad and the lower silicone rubber pad satisfy the constraint condition:
Figure 298290DEST_PATH_IMAGE002
in the above formula, the first and second carbon atoms are,h j is the thickness of the upper silicon rubber pad and the lower silicon rubber pad,h k is the structural height of the single battery installation cavity,h d is the thickness of the unit cell,p d is the internal gas pressure of the battery of the unit cell,A d is the vertical projection area of the single battery,E j is the elastic modulus of the silicon rubber materials of the upper silicon rubber pad and the lower silicon rubber pad,A j the vertical projection areas of the upper silicone rubber pad and the lower silicone rubber pad are provided.
Optionally, the single battery is a gel state polymer lithium ion battery, the gel state polymer lithium ion battery comprises a housing, and a battery anode and a battery cathode which are arranged in the housing, a battery diaphragm is arranged between the battery anode and the battery cathode, and the housing is made of an aluminum plastic film packaging material; the battery positive electrode takes a lithium cobalt oxide alloy material as an active material, and the active material, polyvinylidene fluoride (PVDF) and a conductive agent are mixed to prepare a film to be coated on a positive electrode current collector; the battery cathode takes carbon material graphite as a main active material, and is mixed with polyvinylidene fluoride (PVDF) and a conductive agent to prepare a film to be coated on a cathode current collector; the shell is internally added with gel electrolyte without free liquid.
Optionally, the single battery comprises two tabs horizontally arranged, the two tabs are wrapped by an insulating mounting assembly, the insulating mounting assembly comprises a common lower insulating part and two independent upper insulating parts, each upper insulating part corresponds to one tab, the tabs are clamped between the common lower insulating part and the corresponding upper insulating part, the upper insulating parts, the tabs and the lower insulating parts are stacked in the vertical direction, and the tabs of the single batteries are connected in series or in parallel through a wire connecting piece.
Optionally, the upper cover plate and the lower cover plate are both carbon fiber composite plates coated with insulating material layers, carbon fibers are exposed on the outer side surfaces of the carbon fiber composite plates and connected with grounding terminals, the insulating material layers are arranged on the inner side surfaces of the carbon fiber composite plates, the upper cover plate and the lower cover plate are respectively connected with the grid type framework through connecting pieces, openings are formed in the upper cover plate and/or the lower cover plate, electric connectors for connecting all the single batteries in series/parallel are installed in the grid type battery compartment, and the electric connectors are arranged in the openings in the upper cover plate and/or the lower cover plate.
Optionally, the electrical connector includes a signal electrical connector and a power electrical connector, all the single batteries in the external support structure are connected in series to form a battery pack, and the battery pack is connected to the power electrical connector after being connected in parallel, and the electrical connector further includes a plurality of battery voltage monitoring terminals and a plurality of thermistors, the battery voltage monitoring terminals are connected to a median voltage connection point of each battery pack, and the battery voltage monitoring terminals and the thermistors are connected to the signal electrical connector respectively.
Optionally, the grid-type frame comprises inside grid and the main load frame that locates inside grid all around, inside grid comprises latticed rib, and the junction of arbitrary rib and rib, the junction of rib and main load frame, the junction of main load frame and main load frame all are equipped with cylindrical additional strengthening, be equipped with on the cylindrical additional strengthening and be used for the mounting hole of being connected with upper cover plate, lower cover plate, the cross section of main load frame is "C" shape, just cylindrical additional strengthening fills up the junction of rib and main load frame, the junction of main load frame and main load frame "C" shape recess.
Compared with the prior art, the invention has the following advantages:
1. the invention adopts an external supporting structure consisting of an upper cover plate, a grid type frame and a lower cover plate which are in a sandwich structure to provide bearing capacity, and a plurality of single batteries used for realizing the function of the storage battery pack are arranged in a grid type battery compartment and serve as basic units to realize the function of the storage battery pack, thereby realizing the functions of bearing, supplying and storing electricity, and being beneficial to realizing the miniaturization, integration and compactness of the structures of the spacecraft batteries including satellites and the cabin body.
2. The invention takes the single battery and the accessory structure thereof as the basic cell, and realizes the function of the storage battery pack through the regular combination of the basic cell; the grid type battery cabin structure adaptive to the installation of the basic cell elements is provided, and the consistency of force, electricity and thermal environments in the basic cell elements is ensured while the structure bearing function is realized.
3. The invention reconstructs the grouping mode in the structural lithium battery, reduces redundant parts and further compresses the structural redundancy quality; the design requirements of different satellite structure systems and power supply systems can be met through the expansion of the basic cell elements, and the method has good popularization and application prospects.
Drawings
Fig. 1 is a schematic perspective view of a lithium battery according to an embodiment of the present invention.
Fig. 2 is a schematic perspective exploded view of a lithium battery according to an embodiment of the present invention.
Fig. 3 is a schematic perspective view of a single battery in an embodiment of the invention.
Fig. 4 is a schematic perspective exploded view of a single battery in an embodiment of the invention.
Fig. 5 is a schematic view of an installation structure of a unit cell in an embodiment of the present invention.
Fig. 6 is a schematic diagram illustrating deformation of a single battery during on-rail motion according to an embodiment of the present invention.
Fig. 7 is a schematic perspective view of a grid frame according to an embodiment of the present invention.
Fig. 8 is a schematic circuit diagram of a lithium battery according to an embodiment of the present invention.
Detailed Description
As shown in fig. 1, fig. 2, fig. 3 and fig. 4, the cellular aerospace multifunctional structure lithium battery of the present embodiment includes an external support structure 2 for providing a load-bearing capacity, the external support structure 2 includes an upper cover plate 21, a grid-type frame 22 and a lower cover plate 23, the grid-type frame 22 is provided with a grid-type battery compartment, and a plurality of single batteries 11 for implementing a battery pack function are mounted in the grid-type battery compartment. The grid type battery compartment not only has a battery compartment with uniform specification suitable for installation of the single batteries 11, but also comprises a wiring groove suitable for wiring connected by a circuit. In this embodiment, the inner surface of the battery compartment and the surface of the wire groove of the grid-type battery compartment are insulated by using an insulating film (e.g., a polyimide film), so as to prevent the single batteries 11 from being electrically connected to the compartment.
As shown in fig. 1 and 2, an upper silicone rubber gasket 12 for insulation, heat conduction and vibration reduction is arranged between the single battery 11 and the upper cover plate 21, a lower silicone rubber gasket 13 for insulation, heat conduction and vibration reduction is arranged between the single battery 11 and the lower cover plate 23, a silicone rubber gasket filler is arranged between the periphery of the single battery 11 and the grid-type battery compartment, the upper silicone rubber gasket 12, the lower silicone rubber gasket 13 and the silicone rubber gasket filler are wrapped outside the single battery 11 to form a fully-enclosed structure, the single battery 11, the upper silicone rubber gasket 12, the lower silicone rubber gasket 13 and the silicone rubber gasket filler form a single battery cell assembly 1, the insulation, heat conduction and vibration reduction of the single battery 11 can be realized through the upper silicone rubber gasket 12 and the lower silicone rubber gasket filler, the single battery 11 is integrally suspended and mounted together with the silicone rubber gasket filler, and the generation of large vibration impact response of the single battery 11, and ensures that the single batteries 11 and the grid type battery compartment have good heat conduction performance.
In order to further reduce the large vibration impact response generated by the single battery 11 in the rocket launching process, in this embodiment, the total thickness of the single battery 11, the upper silicone rubber pad 12 and the lower silicone rubber pad 13 is greater than the height of the grid-type frame 22, so that the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are in a pre-pressing state after being installed, the single battery 11 is respectively matched with the upper silicone rubber pad 12 and the lower silicone rubber pad 13 through friction force, the upper silicone rubber pad 12 is matched with the upper cover plate 21 through friction force, the lower silicone rubber pad 13 is matched with the lower cover plate 23 through friction force, the upper silicone rubber pad 12 and the lower silicone rubber pad are combined to enable the single battery 11 to be integrally installed in a suspension manner, and the large vibration impact response generated by the single battery 11 in the rocket launching process can be effectively reduced.
In this embodiment, the single battery 11 is a gel state polymer lithium ion battery (specifically, a lithium cobaltate system is adopted), the gel state polymer lithium ion battery includes a housing, and a battery anode and a battery cathode which are arranged in the housing, and a battery diaphragm is arranged between the battery anode and the battery cathode, wherein:
the shell is made of aluminum plastic film packaging materials (flexible package), so that the size is small, the weight is light, and the energy density and the reliability of the battery can be improved;
the battery positive electrode takes a lithium cobalt oxide alloy material as an active material, and the active material, polyvinylidene fluoride (PVDF) and a conductive agent are mixed to be prepared into a film to be coated on a positive electrode current collector (made of aluminum foil in the embodiment);
the battery cathode takes carbon material graphite as a main active material, and is mixed with polyvinylidene fluoride (PVDF) and a conductive agent to be prepared into a film to be coated on a cathode current collector (in the embodiment, the cathode current collector is made of copper foil);
gel-state electrolyte without free liquid is added in the shell, the whole shell is in a dry state, the dangers of electrolyte leakage, combustion and explosion are prevented, and the whole shell is safe and reliable.
In the embodiment, the battery diaphragm is made of Celgard2500, and is polymerized together by reprocessing and thermal compounding methods, so that the stability and consistency of an interface are ensured, and the electrical property and safety of the polymer lithium battery are improved.
In this embodiment, the single battery 11 has a square shape, a nominal voltage of 3.7V, and a capacity of 10 Ah.
As shown in fig. 3 and 4, the unit cells 11 include two tabs horizontally arranged, and the two tabs are wrapped with an insulation mounting assembly, the insulation mounting assembly includes a common lower insulator 15 and two independent upper insulators 14, each upper insulator 14 corresponds to one tab, the tabs are clamped and arranged between the common lower insulator 15 and the corresponding upper insulator 14, the upper insulators 14, the tabs and the lower insulators 15 are stacked and arranged in a vertical direction, and the tabs of the respective unit cells 11 are connected in series or in parallel by a wire connector. The tab and wire connecting piece mainly realizes the circuit connection between the tab and the series-parallel wires of the battery pack, so that the single battery 11 pack is integrated into the battery pack; the lower insulating part 15 is made of polyimide material, and has better insulating property as a whole; the structure has a strip-shaped configuration, the lower end of the structure is connected with the battery compartment, and the upper end of the structure is matched with the lug and the conductive connecting piece, so that the lug and the conductive connecting piece are not contacted with the ground in the battery compartment, and the circuit conduction between the lug and the structure is avoided; the upper insulating part 14 is made of polyimide material, so that the whole body has better insulating property; the three rectangular surfaces are vertically spliced to form the rectangular battery module by stacking along the vertical direction, the lower end of the rectangular battery module is connected with the lower insulating piece 15, and the tabs and the conductive connecting pieces are integrally covered so that the tabs and the conductive connecting pieces cannot be contacted with the inner wall of the battery compartment and the circuit conduction between the tabs and the conductive connecting pieces and the structure is avoided.
In order to restrain the expansion deformation of the single battery 11 in a vacuum environment, the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 satisfy the constraint condition:
Figure 424247DEST_PATH_IMAGE001
in the above formula, the first and second carbon atoms are,h s the thickness of the silicone rubber pad 12 is,h x the thickness of the lower silicone rubber pad 13,h k for the structural height of the installation cavity of the unit cell 11,h d in order to be the thickness of the unit cell 11,p d is the internal gas pressure of the unit cell 11,A d is the vertical projected area of the unit cell 11,E j the elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown.
In order to simplify production and installation of silicone rubber pad 12, lower silicone rubber pad 13, the thickness of going up silicone rubber pad 12, lower silicone rubber pad 13 equals in this embodiment, the size is the same, the material is the same, and the thickness of going up silicone rubber pad 12, lower silicone rubber pad 13 satisfies the constraint condition:
Figure 246710DEST_PATH_IMAGE002
in the above formula, the first and second carbon atoms are,h j the thickness of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,h k for the structural height of the installation cavity of the unit cell 11,h d in order to be the thickness of the unit cell 11,p d is the internal gas pressure of the unit cell 11,A d is a sheetThe vertical direction projected area of the body cell 11,E j the elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown.
The upper silicone rubber pad 12 and the lower silicone rubber pad 13 need to have a certain thickness so as to provide deformation in the thickness direction to overcome the height difference in the pre-tightening force application process; the height difference is divided by the total thickness (up and down) of the silica gel pad, and then multiplied by the elastic modulus of the material, so that the pretightening force can be preliminarily estimated. However, on the premise that the in-plane envelope size is not changed, the increase in thickness leads to an increase in structural weight, which affects the overall performance (such as functional mass ratio) of the structural lithium battery, so that a plurality of through holes 16 need to be formed in the upper silicone rubber pad 12 and the lower silicone rubber pad 13 to reduce the mass thereof; however, after the through hole 16 is added, the local constraint effect on the lithium battery soft package aluminum plastic film disappears, and the aluminum plastic film can expand, deform or even be damaged. In summary, the size of the through holes 16 of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 needs to be designed without damaging the structural thickness of the lithium battery, so as to achieve the dual functions of weight reduction and negative pressure protection. Therefore, in this embodiment, through holes 16 are formed in the upper silicone rubber pad 12 and the lower silicone rubber pad 13, and the diameter of the through holesr k Satisfies the following conditions:
Figure 576060DEST_PATH_IMAGE003
in the above formula, the first and second carbon atoms are,p d the cell internal gas pressure, min: (of the unit cell 11)h s , h x ) Represents the minimum value of the thicknesses of the upper silicon rubber pad 12 and the lower silicon rubber pad 13,σ m the stress to which the single battery 11 deforms to form a spherical film at the through hole 16 when the spacecraft operates in orbit, min: (h 2 s , h 2 x ) Represents the minimum value of the square of the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,h s the thickness of the silicone rubber pad 12 is,h x is as followsThickness of silicone rubber pad 13. Wherein, the single battery 1 deforms at the through hole 16 to form the stress of the spherical film when the spacecraft works in orbitσ m The formula of the calculation function is:
Figure 774960DEST_PATH_IMAGE004
in the above formula, the first and second carbon atoms are,p d is the internal gas pressure of the unit cell 11,r m the radius of the spherical film is formed by the deformation of the single batteries 11 in the through holes 16 when the spacecraft works in orbit.
The step of determining that the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 meet the constraint condition in this embodiment includes:
1) regarding the space environment as a vacuum state with the air pressure of 0, obtaining the air pressure inside the single battery 11 and the difference delta between the air pressure inside and outside the vacuum environment when the spacecraft works in orbitp=p d Whereinp d The battery internal gas pressure of the unit battery 11;
2) based on the expansion of the unit cells 11 mainly in the thickness direction, the expansion force generated by the unit cells 11 is obtained as follows:
Figure 443839DEST_PATH_IMAGE005
in the above formula, the first and second carbon atoms are,P d in order to generate the swelling force for the unit cells 11,p d is the internal gas pressure of the unit cell 11,A d is the vertical projection area of the single battery 11;
3) referring to fig. 5, consider the thickness of the unit cell 11h d Thickness of silicone rubber pad 12h s Thickness of lower silicone rubber pad 13h x The sum of the three is greater than the height of the battery compartment structure of the single battery 11h k Determining the amount of preload Δ that will be introduced during assembly due to the difference in heighth=(h s +h x +h d )-h k And the pre-tightening force generated correspondinglyP p Comprises the following steps:
Figure 437203DEST_PATH_IMAGE006
in the above formula, the first and second carbon atoms are,E s the elastic modulus of the silicone rubber material of the silicone rubber pad 12,A s is the vertical projection area of the upper silicone rubber pad 12;E x the elastic modulus of the silicone rubber material of the lower silicone rubber pad 13,A x is the vertical projection area of the lower silicone rubber pad 13,E j the elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown; thereby obtaining the expansion forceP d The function of (a) expresses:
Figure 191532DEST_PATH_IMAGE007
in the above formula, the first and second carbon atoms are,h k being the structural height of the battery compartment of the single battery 11,h d in order to be the thickness of the unit cell 11,h s the thickness of the silicone rubber pad 12 is,h x the sum of the thickness of the lower silicone rubber pad 13 is larger than the height of the battery compartment structure of the single battery 11h k ，E j The elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown;
4) to ensure that the cell does not swell to a large extent, a pre-pressure is requiredP p Not less than expansive forceP d Then get the constraint conditionP d ≤P p Substituting into the pre-pressureP p And expansive forceP d The obtained thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 meet the constraint condition:
Figure 928544DEST_PATH_IMAGE008
in the above formula, the first and second carbon atoms are,h s the thickness of the silicone rubber pad 12 is,h x the thickness of the lower silicone rubber pad 13,h k being the structural height of the battery compartment of the single battery 11,h d in order to be the thickness of the unit cell 11,p d is the internal gas pressure of the unit cell 11,A d is the vertical projected area of the unit cell 11,E j the elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown;
5) assuming that the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are equal, the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 satisfy the constraint condition:
Figure 264978DEST_PATH_IMAGE009
in the above formula, the first and second carbon atoms are,h j the thickness of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,h k being the structural height of the battery compartment of the single battery 11,h d in order to be the thickness of the unit cell 11,p d is the internal gas pressure of the unit cell 11,A d is the vertical projected area of the unit cell 11,E j the elastic modulus of the silicone rubber materials of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,A j the vertical projection areas of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are shown.
However, under the premise that the in-plane envelope size is not changed, the increase of the thickness can lead to the increase of the structural weight, and the overall performance (such as functions) of the structural lithium battery is influencedMass ratio, etc.), therefore, a plurality of through holes 16 must be formed on the silica gel pad to reduce the mass thereof; however, after the opening is added, the restraint effect of the part of the lithium battery soft package aluminum plastic film on the opening disappears, and the aluminum plastic film can generate expansion deformation and even damage. In conclusion, the size of the opening of the silica gel pad needs to be designed on the premise of not damaging the structural thickness of the lithium battery, so that the dual functions of weight reduction and negative pressure protection are realized. Thus, the present embodiment also includes determining the aperture of the through-hole 16r k And step (3) of satisfying the constraint condition:
s1), referring to FIG. 6, assuming that the single battery 11 deforms to form a spherical film at the through hole 16 when the spacecraft works in orbit, taking half of the spherical film to calculate the sum of outward expansion forces caused by the difference between the internal air pressure and the external air pressure of the filmP 1/2：
Figure 694823DEST_PATH_IMAGE010
In the above formula, the first and second carbon atoms are,p d is the internal gas pressure of the unit cell 11,r m the radius of the spherical film is formed by the deformation of the single battery 11 in the through hole 16 when the spacecraft works in orbit; at the same time, the sum of outward expansion forces caused by the difference between the internal and external air pressures of the membraneP 1/2And also equal to the sum of the tensions experienced at the film boundaries, expressed as a function of:
Figure 936448DEST_PATH_IMAGE011
in the above formula, the first and second carbon atoms are,σ m the stress to which the single battery 11 deforms to form a spherical film at the through hole 16 when the spacecraft works in orbit,r m the radius of the spherical film is formed by the deformation of the single battery 11 in the through hole 16 when the spacecraft works in orbit;
s2) adding outward expansion force caused by difference of air pressure inside and outside the filmP 1/2The two functional expressions obtain the stress of the single battery 11 on the through hole 16 to form the spherical film when the spacecraft works in orbitσ m The functional expression of (a) is:
Figure 211572DEST_PATH_IMAGE012
in the above formula, the first and second carbon atoms are,p d is the internal gas pressure of the unit cell 11,r m the radius of the spherical film is formed by the deformation of the single battery 11 in the through hole 16 when the spacecraft works in orbit;
s3) radius based on spherical filmr m Stress to which the spherical surface film is subjectedσ m The relationship (c) determines that the maximum tension is obtained when the radius of the film is minimum, determines the condition of the minimum film radius, and the height of the convex part of the film corresponding to the position of the hole is just equal to the thickness of the silicon rubber pad, so that the minimum thickness min (min) of the upper silicon rubber pad 12 and the lower silicon rubber pad 13 is obtainedh s , h x ) Diameter of the through-hole 16r k And radius of spherical surface filmr m Functional relationship between:
Figure 855043DEST_PATH_IMAGE013
s4) according to the minimum thickness min of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 (h s , h x ) Diameter of the through-hole 16r k And radius of spherical surface filmr m Functional relationship between them to obtain the aperture of the through-hole 16r k And the constraint conditions are met:
Figure 252526DEST_PATH_IMAGE014
in the above formula, the first and second carbon atoms are,p d the cell internal gas pressure, min: (of the unit cell 11)h s , h x ) Represents the minimum value of the thicknesses of the upper silicon rubber pad 12 and the lower silicon rubber pad 13,σ m the stress to which the single battery 11 deforms to form a spherical film at the through hole 16 when the spacecraft operates in orbit, min: (h 2 s , h 2 x ) Represents the minimum value of the square of the thicknesses of the upper silicone rubber pad 12 and the lower silicone rubber pad 13,h s the thickness of the silicone rubber pad 12 is,h x the thickness of the lower silicone rubber pad 13.
The silicone rubber pads of the upper silicone rubber pad 12 and the lower silicone rubber pad 13 are made of aerospace-grade silicone rubber, the outer envelope size of the upper silicone rubber pad 12 is 132 × 87 × 2mm, the outer envelope size of the lower silicone rubber pad 13 is 132 × 87 × 2.5mm, and the difference between the upper silicone rubber pad 12 and the lower silicone rubber pad 13 lies in whether the thermistor is mounted in an avoiding groove or not. The upper silicone rubber pad 12, the lower silicone rubber pad 13 and the single batteries 11 have size corresponding relations, and are respectively arranged on the upper surface and the lower surface of each single battery 11, so that the main structure of each single battery 11 is isolated from the battery compartment, the insulativity is ensured, meanwhile, the maximum heat conducting surface of each single battery 11 can be connected, the heat exchange between the single battery and an external supporting structure can be fully carried out, and the heat conducting performance is better; because the elastic modulus of the silicon rubber structure is far smaller than that of an elevator battery, the two vibration reduction pads of the upper silicon rubber pad 12 and the lower silicon rubber pad 13 are added in the heating thickness direction of the single battery 11, and the overall impact resistance and vibration resistance are improved. Go up silicon rubber pad 12, lower silicon rubber pad 13 and be in the pre-compaction state after the installation to realize the cooperation of cell 11 with last silicon rubber pad 12, lower silicon rubber pad 13 through frictional force, and the pre-compaction mode still is favorable to controlling the space negative pressure inflation of cell 11. The silicone rubber pads 13 can be connected with the upper cover plate, the lower cover plate and the single battery 11 through friction force under the action of pre-pressure.
The upper cover plate 21 and the lower cover plate 23 are both carbon fiber composite material plates coated with insulating material layers (polyimide films in this embodiment), the outer side surfaces of the carbon fiber composite material plates are exposed (for example, sandpaper is adopted for polishing) to form carbon fibers and are connected with grounding terminals (the resistance between any two points is not more than 1K omega, so as to ensure that the internal static charge of the upper cover plate is led out), the inner side surfaces of the carbon fiber composite material plates are provided with the insulating material layers, the upper cover plate 21 and the lower cover plate 23 are respectively connected with the grid type frame 22 through connecting pieces, the upper cover plate 21 and/or the lower cover plate 23 are provided with holes, electric connectors for connecting all the single batteries 11 in series/parallel are installed in the grid type battery cabin, and the electric connectors are.
In this embodiment, the upper cover plate 21 is made of M40 carbon fiber composite material, and has a rectangular thin plate configuration as a whole, a thickness of 2mm, and an in-plane dimension determined by the overall dimension of the structural battery compartment. Through holes 16 are arranged in the surface, the circular through holes 16 are used for screw matching, and the specific distribution position and the size are the same as those of the grid type framework structure. The upper cover plate 21 is provided with a square through hole 16 for realizing the connection of the electric connector. The upper surface of the upper cover plate 21 is polished, the insulating composite material basal layer is cleaned, black carbon fibers with conductive performance are exposed, resistance between any two points in the upper surface is measured through a resistance pen and is not more than 1K omega, static charge in the upper cover plate is prevented from accumulating, meanwhile, a grounding pile is arranged on the upper cover plate 21 and is used for leading out static charge in the structure, and accordingly point discharge caused by static charge accumulation is avoided, and the insulation protection of the battery pack is damaged and influenced. The lower surface of the upper cover plate 21 is wrapped by a polyimide film material. The surface is the contact surface of the upper cover plate structure and the single battery cell assembly 1, after the insulation treatment of the polyimide film, the reliability of the insulation design can be further improved, and the double insulation design is formed together with the insulation measure in the single battery cell assembly.
In this embodiment, the lower cover plate 23 is a rectangular thin plate, is made of M40J carbon fiber composite material, and is formed by a laminating process, and has a thickness direction dimension of 1mm and an in-plane dimension the same as that of the upper cover plate 21. The lower cover plate 23 is provided with a circular through hole 16 for matching with the frame structure through hole 16, and a local avoidance through hole 16 is arranged at the position of the heat sensor of the single battery 11. The lower surface of the lower cover plate 23 needs to be polished, the insulating composite material basal layer is cleaned, black carbon fibers with conductive performance are exposed, and the resistance between any two points in the upper surface is measured through a resistance pen and is not more than 1K omega, so that static charges in the upper cover plate can not be accumulated. The upper surface of the lower cover plate 23 is bonded to the grid frame structure 22 to form a battery compartment structure for mounting the unit battery cell assembly 1. After bonding and curing, the inner wall of the cavity (including the upper surface of the lower cover plate 23 and the inner surface of the grid-type frame 22) is insulated by sticking a polyimide film, so that the reliability of the insulation design can be further improved, and the double insulation design is formed together with the internal insulation measures of the single battery cell combination 1.
As shown in fig. 8, the electrical connector in this embodiment includes a signal electrical connector and a power electrical connector, wherein all the single batteries 11 in the external supporting structure 2 are connected in series to form a battery pack, and the battery packs are connected in parallel and then connected to the power electrical connector, and further includes a plurality of battery voltage monitoring terminals and a plurality of thermistors RM1-RM5, wherein the battery voltage monitoring terminals are connected to the median voltage connection points of the battery packs, and the battery voltage monitoring terminals and the thermistors are respectively connected to the signal electrical connector, so that the battery voltage and temperature feedback functions can be realized. In this embodiment, the satellite power supply environment requires that the operating voltage of the battery pack in the power supply system is 21.0V to 29.4V, and the nominal capacity is greater than or equal to 30.0 Ah. The nominal voltage of the single lithium ion battery of the lithium cobaltate system is 3.7V, the working voltage is 3.0V-4.2V, and the capacity is 10.0 Ah. Therefore, 21 single batteries can be adopted to meet the power supply requirement. Because the inside design of cell element form that has of group battery, the series connection mode between the utmost point ear is realized more easily, only needs to carry out the fluting to a rib of battery interval, consequently adopts the battery combination mode of 7 strings 3 parallels, and 3 group batteries are 7 earlier establish ties, establish ties good back and realize the parallel operation of 3 group batteries and constitute complete group battery. Collecting the voltage Vi (i is a serial mark symbol) of the anode of the middle single battery of each battery pack to the power ground, and using the voltage Vi as the monitoring voltage of the battery state; in the normal state, the monitored voltage values should be substantially equal (maximum voltage difference ≦ 50 mV). Collecting temperature signals of single batteries at the center and four corner positions of the battery pack measured by 5 thermistors RM1-RM5 respectively; the temperature environment can seriously affect the charge and discharge performance of the battery, the single battery is required to work in the temperature environment of 15-20 ℃, the internal temperature of the structural battery needs to be approximately and uniformly distributed, and the temperature deviation is not more than 3 ℃; the formed battery pack is connected with the power supply control unit through the power electric connector to realize charge and discharge control. The collected 3 battery state monitoring voltages and 5 thermistor temperatures are connected with a power supply control unit through a signal electric connector, so that the effective monitoring of the power supply state is realized.
As shown in fig. 7, the grid-type frame 22 is composed of an inner grid and main force-bearing frames arranged around the inner grid, the inner grid is composed of latticed ribs, and the joints of any ribs and ribs (see the reference number c in the figure), the joints of the ribs and the main bearing frame (see the reference number b in the figure), and the joints of the main bearing frame and the main bearing frame (see the reference number a in the figure) are all provided with cylindrical reinforcing structures, the cylindrical reinforcing structures are provided with mounting holes for connecting with the upper cover plate 21 and the lower cover plate 23, by the structure, the grille type frame 22 can achieve the effects of light weight and high strength at the same time, and each corner of the grid type frame 22 can be connected with the upper cover plate 21 and the lower cover plate 23 by bolts, so that the structural strength and the bearing performance of the external support structure 2 are ensured, and the bearing requirements of the launching process and the on-orbit operation of the spacecraft are met.
In addition, in order to further reduce the mass of the grid-type frame 22 and maintain the strength, as shown in fig. 7, the cross section of the main force-bearing frame in this embodiment is "C" shaped, and the cylindrical reinforcing structure fills the "C" shaped grooves at the joints of the ribs and the main force-bearing frame (see the reference sign b in the figure) and at the joints of the main force-bearing frame and the main force-bearing frame (see the reference sign a in the figure).
In this embodiment, the grid-type frame 22 is integrally formed in a rectangular grid-like configuration, and is formed by a mold pressing process using M40 carbon fiber composite material; the whole frame structure is composed of four frames and a plurality of rib structures, and the whole appearance has the characteristic of a grid shape. The four main bearing frames of the frame structure are respectively positioned at the four outer sides of the frame structure and are made of a composite material slotted beam structure with a C-shaped section, and the enveloping dimension of the section is 12mm multiplied by 11.0mm (in the thickness direction). The design mode can ensure that the whole structure has stronger structural rigidity and effectively reduces the structural weight; the thickness of the frame component is divided into 1mm and 2mm, wherein the layering mode of the 1mm thick basic carbon fiber board is 0/45/-45/0/0/-45/45/0, and the 2mm thick board fiber board is formed by stacking two layers of 1mm thick basic carbon fiber boards. Structural perforation design is carried out at the connection positions of the frame and the connection positions of the frame and the ribs, and a reinforcing structure is added at the perforation positions to fill the cross section of the C-shaped groove, so that the connection rigidity of the frame structure is ensured. The diameters of the mounting holes on the frame are 4.5mm, and the distance from the outer edge of the frame to the outer edge of the frame is 6 mm. The rib structure is a secondary bearing structure in the frame and mainly plays a role in separating the single batteries and providing an installation interface for the electric connector. The rib has "I" type cross-section, and thickness direction size is 2mm, and direction of height size is 11.5mm (keeping unanimous with the battery compartment size), and the shop puts the mode and is unanimous with four frames of frame construction. The frame and the ribs of the frame structure form a grid structure, the space size isolated by the grid is used for installing the single battery cell combination, and the space size is the same and is 148mm multiplied by 91mm multiplied by 11.0 mm. The local reinforcement is added at the intersection point of the ribs, the reinforcement area is cylindrical, the diameter of the cylinder is 8mm, and a through hole 16 with the diameter of 3.4mm is drilled at the center of the reinforcement structure so as to meet the requirement of matching with a structural hole. And according to the wiring requirement, avoiding design is carried out on the ribs. In view of facilitating the wiring operation, a grooved form is adopted instead of the open-hole form. In order to influence the structural rigidity and strength of the rib as much as possible, the opening depth is small. In order to meet the installation requirement of the electric connector, two electric connector installation interfaces are additionally arranged on the structural lithium battery frame. The signal electric connector mounting interface is positioned at the intersection position of the frame and the ribs and consists of two mounting joints with embedded threaded holes, and the signal electric connector is directly connected with the mounting interface. The thread throwing fixing piece mounting interface is positioned at the intersection position of the frame and the rib, consists of two mounting joints with embedded threaded holes and is directly connected with the thread throwing fixing piece; the power electric connector adopts a wire throwing mode, is not directly connected with the structure, and fixes the cable on the frame through a wire throwing fixing piece; the mounting screw hole is matched with an M3 thread, and the length of the thread is determined according to the mounting requirement of the aerospace machinery.
As an optional implementation manner, in this embodiment, each single battery 11 is assembled by using uniform components, and the geometric size, structural composition, and boundary conditions of each component are the same, and the conditions of impact resistance, heat conduction, and insulation protection are all the same, so that the expansion design and application are facilitated according to different energy system requirements, and the single battery is suitable for various types of spacecraft including satellites.
In addition, the present embodiment further provides a circuit system grouping method capable of maintaining internal impedance balance while avoiding single-point failure of a circuit by introducing a single-point dual-wire connection method and a connection wire long-wire control method, where the circuit system grouping method is as follows: first, series-parallel connection of the battery packs themselves is performed, and battery pack assembly and line connection are performed. The cables related to the internal single batteries are strong current cables, the connection and wiring of the cables are all arranged on one side of the battery pack, and the cables penetrate through the ribs in a punching mode. All the series lines, the positive power lines and the negative power lines are equal in length, and the line resistance is guaranteed to be consistent. The specific connection requirements are as follows: firstly, 7 single batteries in each series are respectively positioned in 7 transverse cavities of the grid type framework, and the positive and negative electrodes are connected in series through a wire groove on a rib; secondly, 3 rows are distributed corresponding to 3 strings of batteries, and the positive electrodes and the negative electrodes of the 3 strings of battery packs are connected in parallel through wiring grooves at two ends of the grid type frame; the series and parallel connection wires are connected in a single-point double-wire mode, so that single-point failure caused by open circuit risks is avoided; fourthly, the voltage of each battery string is ensured to be as close as possible through reasonable screening and matching, and the batteries are prevented from being damaged by instant heavy current discharge; preparing connecting wires with the same length, and ensuring that the impedance of each series of batteries introduced by connection is consistent through the same connecting process. And secondly, connecting the assembled battery pack with a power electric connector. The battery pack obtained by connecting the single batteries in series and parallel is connected with the power electric connector through 14 leads, so that the structural lithium battery has a charge-discharge interface. The connection requirements are specified below: 15 contacts of the power electric connector, wherein the contact No. 1 is empty, and the other 14 contacts are divided into two groups and are respectively connected with the anode and the cathode of the battery pack; 7 14 # 20 leads are used as battery positive connecting wires, and 7 leads are used as battery negative connecting wires; the positive and negative connecting wires are divided into 3 groups according to a 2-2-3 mode, and are respectively connected with the positive and negative electrodes of 3 series of battery packs, so that the failure of single-point connection is avoided; and the length of the specific wire needs to ensure that the cable is as short as possible and the introduced impedance is distributed uniformly. And thirdly, connecting the battery pack with the signal electric connector. The 3 strings of battery packs are connected with the signal electric connector through 8 medium voltage detection cables, so that the structural lithium battery has a medium detection function and is used for judging whether the voltage of the single battery in each string of batteries is normal. The connection requirements are specified below: the signal electric connector comprises 37 nodes, wherein 8 nodes are used for connecting a median detection cable; 8 # leads are divided into 4 groups by adopting a main backup mode, the first three groups are used for connecting the anode of a third section of single battery of each series of battery packs with an electric connector, and the last group is used for connecting the cathode of a second series of battery packs with the electric connector; the lead joint connection process is safe and reliable, and can meet the rated working current and I-level derating requirement (50%); and fourthly, the length of the specific lead needs to ensure that the cable is as short as possible and the introduced impedance is distributed uniformly. And finally, connecting the thermistor with a signal electric connector. The thermistor should be disposed at a position where a temperature extreme value may occur, so as to evaluate the temperature distribution section of the entire battery. Because the whole structure battery has the flat plate characteristic, the number of only two single batteries surrounding the four corner points is minimum, and the periphery of the single battery at the geometric center is surrounded by the single battery, the heat at the corner point positions is more transferred outwards, the temperature is lower, the heat at the central position is less transferred outwards, the temperature is higher, and the thermistor is provided with the four corner points (WC 01-WC 04) and the geometric center point (WC 05) for 5 in total. 5 thermistors are connected with the signal electric connector through 10 leads, so that the structural lithium battery has the temperature detection function of a single battery. Specific wire connection requirements are specified below: firstly, 10 contacts in the signal electric connector model are used for connecting positive and negative leads of a thermistor; secondly, inside the structural lithium battery, the communication and layout of internal leads are realized through the grooves on the ribs; and the length of the specific wire needs to ensure that the cable is as short as possible and the introduced impedance is distributed uniformly.
As can be seen from the foregoing, in terms of the design of insulation and ground protection, the following measures are adopted in the present embodiment: aiming at the main structure of the soft package lithium ion battery, a multiple insulation protection mode of combining an aluminum plastic film, a silica gel pad, silicon rubber and a polyimide film is provided; aiming at a soft package lithium ion battery tab structure, a multiple insulation protection mode combining an insulation piece, silicon rubber and a polyimide film is provided; aiming at the circuit connecting wire, a combined multiple insulation protection mode of 'insulation protection layer + heat-shrinkable sleeve + insulation piece gap wiring' is provided. By the mode, reliable insulation and grounding protection can be realized.
Wherein, the content of insulation protection design includes: firstly, the main structure of the single battery is subjected to multiple insulation treatments. The main structure of the soft package single lithium ion battery is insulated from the outside only through an aluminum plastic film. The aluminum-plastic film has poor structural strength, is easily punctured by a sharp object, loses the insulation protection function, causes lap connection and conduction between the battery pack and the satellite structure ground, and influences the balance of the electric potential of the cabin board and the whole satellite. In order to ensure the insulation between the main structure of the single battery and the external supporting structure, multiple insulation treatments are carried out between the main structure of the single battery and the external supporting structure: firstly, through appearance inspection, a single battery with damaged appearance is provided, and a complete single battery with an outer layer of an aluminum-plastic film is selected to play an insulation effect; the upper and lower silica gel pads are additionally arranged between the single battery and the upper and lower cover plates for isolation, the single battery is bonded and protected with the grid type frame through silicon rubber, the single battery is suspended and installed through the silicon rubber, and the single battery is not in direct contact with a structural body; sticking polyimide adhesive tapes on the lower surface of the upper cover plate, the upper surface of the lower cover plate and the inner surface of the grid type frame to keep the insulativity of the battery mounting cavity. Secondly, the single battery pole ear is subjected to various insulation treatments. The positive and negative electrode lugs of the single battery are all made of bare metal materials. If the insulation protection cannot be well carried out, the lapping short circuit of the positive electrode and the negative electrode or the conduction of the electrode lug and an external supporting structure are easily caused, and the short circuit accident is caused. In order to ensure the insulativity of the single battery tab, multiple insulation treatments are required to be implemented: firstly, fixing a lug on a customized insulating piece, and isolating the lug from an upper cover plate, a lower cover plate and a grid type frame structure through an upper insulating piece and a lower insulating piece; on the basis of the installation of the insulating parts, the metal surface of the exposed lug is basically controlled in the space surrounded by the upper insulating part and the lower insulating part, silicon rubber is further filled in the cavity, the lug is isolated from an external structure by utilizing the insulating property of the silicon rubber, and the lap joint short circuit of the positive lug and the negative lug is avoided; and thirdly, similar to the insulation protection of the main structure of the single battery, a polyimide adhesive tape is pasted on the lower surface of the upper cover plate, the upper surface of the lower cover plate and the inner surface of the grid type frame, so that the insulation property of the battery installation cavity is kept. And thirdly, performing multiple insulation treatment on the connecting lead. When power cable and series-parallel connection cable because of insulation protection is improper, cause easily that the short circuit takes place between the positive negative pole wire and between with outside bearing structure, influence the holistic insulating nature of cell type structure lithium cell, need implement multiple insulation and handle: firstly, an insulating layer wraps the outer layer of the wire, and the wire is fixed by silicon rubber at the position where the wire is contacted with the structure after being wrapped by a thermoplastic sleeve, so that the wire is prevented from swinging greatly and being rubbed to damage the insulating layer; the lithium battery with the structure has dozens of leads, and in order to ensure the lead trafficability, the leads are distributed and communicated through the slots set at the positions of the ribs, so that the leads are wrapped by thermoplastic sleeves at the positions which are possibly contacted with sharp edges, such as the through holes, the ridges and the like, and are fixed with the structure by silica gel; and the size of the lower insulating part is larger than that of the upper insulating part, and the lower insulating part is close to the battery cavity when being installed, so that a gap is formed between the cavity and the upper insulating part. The inner space of the insulating part is utilized to penetrate through the series connection lead of the single battery, the gap is utilized to penetrate through the power lead, and space isolation exists between the two, so that short circuit risk is avoided. Aiming at the short circuit occurrence position, multiple insulation measures are respectively taken aiming at the main structure, the lug and the connecting lead of the soft package lithium ion battery in the single battery cell element assembly, so that a good insulation environment is provided for the internal structure of the cell element type structure lithium battery.
Wherein, the content of the ground protection design includes: compared with the traditional structure lithium battery, the single battery structure is designed to be in multiple insulation through the cell design in the cell type structure lithium battery, so that the battery pack has good insulation and reliability, high-resistance grounding of the battery pack is avoided, and accumulated static charges are led out only by adopting the grounding pile. The grounding pile is made of aluminum alloy and is arranged on the upper surface of the upper cover plate. In order to ensure that static electricity in the structure lithium battery is well discharged, the upper cover plate grounding assembly is formed in a mode that the conductive copper foil is matched with the grounding pile. The conductive copper foils adhered to the upper surface and the lower surface of the upper cover plate can increase the conductivity between the grounding pile and the upper cover plate, the grounding pile and the upper cover plate are all in a circular ring configuration, and the center of the conductive copper foils corresponds to the center of the mounting hole of the grounding pile. And the grounding pile penetrates through the opening of the upper cover plate and is fixed through the fastening nut, and the grounding pile and the conductive copper foil are in mechanical connection and charge conduction relation.
In the aspect of electromagnetic compatibility design, in the structural design of the single battery cell assembly 1, the design and the installation mode of the insulating part are reasonable, the gap between the insulating part and the battery cavity is expanded and used, and the area enclosed by the conducting wires is reduced as much as possible while the insulation between the conducting wires is ensured by the solid line, so that the electromagnetic interference caused by the circuit connection of the lithium battery with the cell structure is reduced. The electromagnetic compatibility of the structural lithium battery mainly considers a strong electric working module and sensitive electronic elements. The battery pack is a strong current module, and is used for connecting a solar battery array during charging, storing energy in the battery and supplying power to a bus power supply during discharging. The charge and discharge process of the internal storage battery pack mainly generates electrochemical reaction, and the working of the internal storage battery pack is not influenced by electromagnetic compatibility due to the characteristics of the internal storage battery pack. The thermistor, the heating sheet, the lead and the like in the equipment are not inductive electronic elements, the working current of the thermistor is small, and residual magnetism cannot be generated. Only the area and the effective current surrounded by the wire connecting circuit are used as the calculation basis for checking the electromagnetic performance. The wires are connected with small wires by bringing the positive and negative leads of the battery close to each other. However, when the positive and negative leads are close to each other, the risk of short circuit is easily caused. The problem is not solved, and the following measures are adopted in the design process of the lithium battery with the cell type structure: firstly, a polyimide film is pasted on the inner surface of the battery cavity, so that the positive and negative leads are prevented from being grounded through a structure, and a short circuit is formed; secondly, in the structural design of the single battery cell assembly, the size of the lower insulating part is larger than that of the upper insulating part, and the lower insulating part is close to the battery cavity when being installed, so that a gap is formed between the cavity and the upper insulating part. And thirdly, because the upper insulating part, the lower insulating part and the battery cavity are subjected to insulating treatment, when the gap is utilized to penetrate through a lead, the risk of short circuit is avoided. And penetrating the series lead of the single battery by using the inner space of the insulating part, and connecting the anode lead wire at the rightmost end to the power electric connector through the gap. The two wires are surrounded to form an area which is as small as possible, and the two wires are respectively provided with better insulation protection. Taking the peak state internal current of three strings as an example, the corresponding single string battery current is 8.3A. Because the parallel wires do not form an effective loop and do not count the calculation, the remanence of the battery pack power circuit can be formed by superposing the remanence of 3 strings of batteries:
Figure 981448DEST_PATH_IMAGE015
in the formula: phi is remanence;Sis the area enclosed by the ring;Iis the current in the circuit.
In addition, in the embodiment, by introducing an over-matching mode in the battery assembling process, under the assembled state of the single battery, the pre-tightening force for limiting expansion is applied to the upper surface and the lower surface of the single battery; the pre-tightening force is generated because the height of the grid type frame structure is smaller than the height of the battery and the silica gel pad; during assembly, a matching relation exists between the upper and lower silicon rubber pads, the upper and lower silicon rubber pads are compressed due to the height difference, the single battery is of a laminated structure, the rigidity in the thickness direction is high, the compression amount is small and can be ignored; therefore, the compression elastic force of the silica gel pads exists on the upper surface and the lower surface of the single battery. The pretightening force can be offset with the expansion force of the single battery in the space environment through reasonable design, so that the expansion deformation of the single battery is limited, and the single battery cannot be damaged due to negative pressure.
The cell type space multifunctional structure lithium battery is successfully applied to a certain satellite, flight test results show that the bearing capacity of the structure can resist and meet the requirement of rocket launching impact vibration environment, the storage battery pack has stable on-orbit power storage and power supply functions, electric energy generated by the solar battery array is stored in the sun area, and energy is continuously provided for loads and equipment on the satellite in the launching section and the shadow area.
The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may occur to those skilled in the art without departing from the principle of the invention, and are considered to be within the scope of the invention.

Claims (8)

1. The utility model provides a cell type space flight multifunctional structure lithium cell, its characterized in that, including the outside bearing structure (2) that is used for providing bearing capacity, outside bearing structure (2) are including upper cover plate (21), grid formula frame (22) and lower apron (23) that are sandwich structure, just be equipped with grid formula battery compartment in grid formula frame (22), install polylith battery cell (11) that are used for realizing the storage battery function in the grid formula battery compartment, be equipped with between battery cell (11) and upper cover plate (21) and be used for insulating, heat conduction and damping last silicone rubber pad (12), and be equipped with between apron (23) down silicone rubber pad (13) that are used for insulating, heat conduction and damping, be equipped with the packing silicone rubber pad around battery cell (11) and between the grid formula battery compartment, it wraps up at battery cell (11) outside formation full enclosure structure of three at silicone rubber pad (12), lower silicone rubber pad (13) and packing silicone rubber pad The utility model discloses a solar cell, monomer battery (11), last silicone rubber pad (12), silicone rubber pad (13) down and fill silicone rubber pad and constitute monomer battery cell element assembly (1), the gross thickness of monomer battery (11), last silicone rubber pad (12), lower silicone rubber pad (13) is greater than the height of grid formula frame (22) for last silicone rubber pad (12), lower silicone rubber pad (13) are in the pre-compaction state after the installation, through the frictional force cooperation between monomer battery (11) respectively with last silicone rubber pad (12), lower silicone rubber pad (13), go up between silicone rubber pad (12) and upper cover plate (21) through the frictional force cooperation, through the frictional force cooperation between lower silicone rubber pad (13) and lower cover plate (23), the thickness of going up silicone rubber pad (12), lower silicone rubber pad (13) satisfies the constraint condition:
Figure 464611DEST_PATH_IMAGE001
in the above formula, the first and second carbon atoms are,h s is the thickness of the upper silicon rubber pad (12),h x is the thickness of the lower silicone rubber pad (13),h k the structural height of the installation cavity of the single battery (11),h d is the thickness of the single battery (11),p d is the internal gas pressure of the single battery (11),A d is the vertical projection area of the single battery (11),E j is the elastic modulus of the silicon rubber materials of the upper silicon rubber pad (12) and the lower silicon rubber pad (13),A j the vertical projection areas of the upper silicone rubber pad (12) and the lower silicone rubber pad (13) are provided.
2. The lithium battery with a cellular aerospace multifunctional structure according to claim 1, wherein the upper silicone rubber gasket (12) and the lower silicone rubber gasket (13) have the same thickness, the same size, and the same material, and the thicknesses of the upper silicone rubber gasket (12) and the lower silicone rubber gasket (13) satisfy the constraint condition:
Figure 381752DEST_PATH_IMAGE002
in the above formula, the first and second carbon atoms are,h j is the thickness of the upper silicon rubber pad (12) and the lower silicon rubber pad (13),h k the structural height of the installation cavity of the single battery (11),h d is the thickness of the single battery (11),p d is the internal gas pressure of the single battery (11),A d is the vertical projection area of the single battery (11),E j is the elastic modulus of the silicon rubber materials of the upper silicon rubber pad (12) and the lower silicon rubber pad (13),A j the vertical projection areas of the upper silicone rubber pad (12) and the lower silicone rubber pad (13) are provided.
3. The cell type aerospace multifunctional structure lithium battery according to claim 1, wherein the single battery (11) is a gel state polymer lithium ion battery, the gel state polymer lithium ion battery comprises a housing, a battery anode and a battery cathode arranged in the housing, a battery diaphragm is arranged between the battery anode and the battery cathode, and the housing is made of an aluminum plastic film packaging material; the battery positive electrode takes a lithium cobalt oxide alloy material as an active material, and the active material, polyvinylidene fluoride (PVDF) and a conductive agent are mixed to prepare a film to be coated on a positive electrode current collector; the battery cathode takes carbon material graphite as a main active material, and is mixed with polyvinylidene fluoride (PVDF) and a conductive agent to prepare a film to be coated on a cathode current collector; the shell is internally added with gel electrolyte without free liquid.
4. The cell type lithium battery with an aerospace multifunctional structure according to claim 1, wherein the unit cells (11) comprise two tabs arranged horizontally, and the two tabs are wrapped with an insulation mounting assembly, the insulation mounting assembly comprises a common lower insulator (15) and two independent upper insulators (14), each upper insulator (14) corresponds to one tab, the tabs are clamped and arranged between the common lower insulator (15) and the corresponding upper insulator (14), the upper insulators (14), the tabs and the lower insulators (15) are stacked and arranged in a vertical direction, and the tabs of the unit cells (11) are connected in series or in parallel through a wire connector.
5. The cell type aerospace multifunctional structure lithium battery according to claim 1, wherein the upper cover plate (21) and the lower cover plate (23) are both carbon fiber composite plates coated with insulating material layers, the outer side surfaces of the carbon fiber composite plates are exposed to carbon fibers and connected with grounding terminals, the inner side surfaces of the carbon fiber composite plates are provided with insulating material layers, the upper cover plate (21) and the lower cover plate (23) are respectively connected with the grid type frame (22) through connecting pieces, the upper cover plate (21) and/or the lower cover plate (23) are provided with openings, the grid type battery compartment is provided with electrical connectors for connecting all the unit batteries (11) in series/parallel, and the electrical connectors are arranged in the openings of the upper cover plate (21) and/or the lower cover plate (23).
6. The cell type aerospace multifunctional structure lithium battery according to claim 5, wherein the electrical connectors comprise a signal electrical connector and a power electrical connector, all the single batteries (11) in the external support structure (2) are connected in series to form a battery pack, the battery packs are connected in parallel and then connected with the power electrical connector, the aerospace multifunctional structure lithium battery further comprises a plurality of battery voltage monitoring terminals and a plurality of thermistors, the battery voltage monitoring terminals are connected with the median voltage connection points of the battery packs, and the battery voltage monitoring terminals and the thermistors are respectively connected with the signal electrical connector.
7. The lithium battery with cellular aerospace multifunctional structure of claim 1, wherein the grid-type frame (22) comprises an inner grid and a main bearing frame arranged around the inner grid, the inner grid comprises grid-shaped ribs, and cylindrical reinforcing structures are arranged at the joints of any rib and rib, the joints of any rib and main bearing frame, and the joints of any main bearing frame and main bearing frame, and the cylindrical reinforcing structures are provided with mounting holes for connecting with the upper cover plate (21) and the lower cover plate (23).
8. The cell type aerospace multifunctional structural lithium battery of claim 7, wherein the cross section of the main force bearing frame is "C" shaped, and the cylindrical reinforcing structure fills the C-shaped grooves at the joints of the ribs and the main force bearing frame and the joints of the main force bearing frame and the main force bearing frame.
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CN113793971A (en) * 2021-08-29 2021-12-14 西北工业大学 High-heat-conductivity lithium battery pack for underwater vehicle

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