Columnar battery cell and power battery

Abstract

The invention relates to the technical field of power batteries, and particularly discloses a columnar battery cell and a power battery, and the columnar battery cell comprises a shell, a cover plate assembly and a bottom plate assembly. The shell comprises an inner shell and an outer shell. The cover plate assembly is connected to the end, provided with the first opening, of the inner shell. The bottom plate assembly is connected with the end, provided with the second opening, of the shell, the inner shell, the cover plate assembly and the bottom plate assembly define a first containing space used for installing a pole group, and the inner shell, the outer shell and the bottom plate assembly define a second containing space used for being filled with a phase change material. When the pole group works, the phase change material in the second accommodating space can absorb or release heat, so that the pole group is at a better working environment temperature, the service life of the columnar battery cell is prolonged, and the heat management capability is good. And the second accommodating space is arranged in the circumferential direction of the first accommodating space, so that the pole group is uniform in heat dissipation and good in temperature uniformity. The invention also provides a power battery which comprises the columnar battery cell.

Description

Technical Field

[0001] The present invention relates to the technical field of power batteries, and in particular to a cylindrical battery cell and a power battery. Background Art

[0002] Power batteries are now widely used as power sources for electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles, thereby solving problems such as air pollution caused by vehicles using petroleum fuels. One or more battery cells may be used in a power battery, and each battery cell is provided with multiple battery cells. Common types of battery cells include square shell cells, blade cells, and cylindrical cells. Due to the high integration of battery cells in power batteries, the charging characteristics of battery cells will decrease when the temperature rises or drops sharply, and the charging efficiency will decrease. If the battery cell is continuously charged at too high a temperature, the cycle life of the battery cell will also be shortened. In addition, if the battery cell is continuously charged or operated at too low a temperature, some battery cells may be damaged. Therefore, it is necessary to ensure that the battery cell is charged and discharged at a reasonable working environment temperature to ensure good performance and a long service life of the power battery.

[0003] For common cylindrical cells, if the working environment temperature is too high, the side expansion of the cylindrical cell shell will be serious. This requires that expansion space be reserved when installing the cylindrical cell, which will increase the ineffective space in the power battery and reduce the energy of the power battery. Therefore, it is necessary to perform good thermal management on the power battery to control the working environment temperature of the cylindrical cell. At the same time, the internal space of the power battery should be reasonably arranged to improve space utilization. Summary of the invention

[0004] The object of the present invention is to provide a columnar battery cell and a power battery. The columnar battery cell has good thermal management capability and a reasonable working environment temperature, which is conducive to extending the service life of the columnar battery cell. At the same time, the internal space layout of the power battery is reasonable and the space utilization rate is high.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides a cylindrical battery cell, comprising:

[0007] The housing comprises an inner housing and an outer housing, wherein the inner housing is cylindrical and has a first opening and a second opening at two opposite ends along a first direction, and the outer housing is polygonal and is sleeved outside the inner housing;

[0008] A cover plate assembly connected to one end of the inner shell provided with the first opening;

[0009] A bottom plate assembly is connected to one end of the shell body provided with the second opening, the inner shell, the cover plate assembly and the bottom plate assembly are arranged to form a first accommodation space, the first accommodation space is used to install the pole group, the inner shell, the outer shell and the bottom plate assembly are arranged to form a second accommodation space, the second accommodation space is used to fill the phase change material;

[0010] The total volume of the phase change material injected into the second accommodation space when it is in liquid state is V1, and the total volume of the second accommodation space is V;

[0011] V1 and V satisfy the following condition: 0.5≤V1 / V≤0.95.

[0012] Optionally, the outer shell includes a plurality of side plates connected in sequence, the side plates are in the shape of flat plates, and the side plates are tangent to the outer wall surface of the inner shell, and the contact points between the side plates and the outer wall surface of the inner shell form a linear connection portion, the connection portion extends along the first direction, and the connection portion divides the second accommodating space into a plurality of subspaces, and the phase change material is arranged in each of the subspaces;

[0013] The total cross-sectional area of ​​all the subspaces is S1, and the cross-sectional area of ​​the shell is S2; S=S1+S2; S1 and S satisfy: 0.5≤S1 / S≤0.9.

[0014] Optionally, the shell includes a plurality of first sealing members, and the first sealing member in each of the subspaces is used to seal a first opening of the subspace along the first direction close to one end of the cover plate assembly.

[0015] Optionally, the first sealing member includes an end plate, a first sealing plate, a second sealing plate and a third sealing plate, the first sealing plate, the second sealing plate and the third sealing plate are all connected to one side of the end plate along the first direction, the first sealing plate, the second sealing plate, the third sealing plate and the end plate form a receiving groove, the receiving groove is connected to the subspace, the first sealing plate and the second sealing plate are respectively attached to the inner wall surface of one of the side plates, and the third sealing plate is attached to the outer wall surface of the inner shell.

[0016] Optionally, one side of the end plate connected to the first sealing plate and the second sealing plate extends in a direction away from the inner shell to form a lap joint, the lap joint is connected to the end of the side plate along the first direction, and the end of the lap joint away from the end plate is flush with the outer wall surface of the side plate.

[0017] Optionally, the bottom plate assembly is separately arranged from the shell, and the bottom plate assembly includes a bottom plate body and a plurality of second seals, the bottom plate body is connected to one end of the inner shell provided with the second opening and seals the second opening, the number of the second seals is the same as that of the first seals and the subspaces and they correspond one to one, and the second seal in each subspace is used to seal the second opening of the subspace along the first direction away from the side of the cover plate assembly.

[0018] Optionally, the structure of the second sealing member is the same as that of the first sealing member.

[0019] Optionally, the bottom plate assembly is integrally formed with the shell, and the bottom plate assembly includes a bottom plate body, and the bottom plate body is used to block the second opening of the inner shell and block the second opening of each subspace along the first direction away from the cover plate assembly.

[0020] Optionally, the cover plate assembly includes a cover plate body and a pole, the cover plate body is connected to one end of the inner shell provided with the first opening and blocks the first opening, the positive pole of the pole group is electrically connected to the pole, and the negative pole of the pole group is electrically connected to the shell.

[0021] On the other hand, the present invention provides a power battery, including a battery box and at least one battery cell, wherein the battery cell is arranged in the battery box, and each of the battery cells includes a plurality of columnar battery cells according to any of the above schemes.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a columnar battery cell, comprising a shell, a cover plate assembly and a bottom plate assembly. The shell comprises an inner shell and an outer shell, and the cover plate assembly is connected to one end of the inner shell provided with a first opening, and blocks the first opening of the inner shell. The bottom plate assembly is connected to one end of the shell provided with a second opening, and the inner shell, the cover plate assembly and the bottom plate assembly are surrounded to form a first accommodation space, and the first accommodation space is used to install the pole group, and the inner shell, the outer shell and the bottom plate assembly are surrounded to form a second accommodation space, and the second accommodation space is used to fill the phase change material. When the temperature of the pole group is high or low, the phase change material in the second accommodation space can absorb or release heat, so that the pole group is at a better working environment temperature, which is conducive to extending the service life of the columnar battery cell and has good thermal management capabilities. And because the second accommodation space is arranged around the circumference of the first accommodation space, the heat can be evenly dissipated around the pole group, the thermal management effect is good, and the temperature uniformity of the pole group is good.

[0024] The present invention also provides a power battery, including a battery box and at least one battery cell, wherein the battery cell is arranged in the battery box, and each battery cell includes a plurality of columnar cells. By adopting the above-mentioned columnar cells, when a plurality of columnar cells are grouped, adjacent columnar cells can fit each other, or be arranged at a small interval, thereby facilitating the improvement of the space utilization rate of the battery cell in the battery box and making rational use of the space. At the same time, the columnar cells themselves have good thermal management capabilities, and the columnar cells can be charged and discharged at the optimal working environment temperature, so that the power battery has excellent performance and a long service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0026] Figure 1 An exploded view of a cylindrical battery cell provided in Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a columnar battery cell provided in the first embodiment of the present invention;

[0028] Figure 3 A top view of a cylindrical battery cell provided in Embodiment 1 of the present invention;

[0029] Figure 4 for Figure 3 Sectional view of the AA section;

[0030] Figure 5 for Figure 4 A partial enlarged view of point B in the middle;

[0031] Figure 6 for Figure 4 A partial enlarged view of point C in the middle;

[0032] Figure 7 This is a schematic structural diagram of the first sealing member (second sealing member) provided in the first embodiment of the present invention;

[0033] Figure 8 This is a schematic structural diagram of the first sealing member (second sealing member) provided in the first embodiment of the present invention from another viewing angle;

[0034] Fig. 9 A cross-sectional view of a shell of a columnar battery cell provided in the second embodiment of the present invention;

[0035] Fig.10 for Fig. 9 A partial enlarged view of point D in the middle;

[0036] Fig.11 A top view of a shell of a columnar battery cell provided in Embodiment 3 of the present invention;

[0037] Fig.12 for Fig.11 Sectional view of the EE section;

[0038] Fig.13 for Fig.12 A partial enlarged view of the F in the middle;

[0039] Fig.14 A cross-sectional view of a shell of a columnar battery cell provided in a fourth embodiment of the present invention;

[0040] Fig.15 for Fig.14 A partial enlarged view of point G in the middle.

[0041] In the figure:

[0042] 100, shell; 110, inner shell; 1101, first accommodating space; 120, outer shell; 1201, subspace; 121, side plate; 122, connecting part; 130, first sealing member; 1301, accommodating groove; 131, end plate; 1311, overlapping part; 132, first sealing plate; 133, second sealing plate; 134, third sealing plate; 200, cover plate assembly; 210, cover plate body; 220, pole; 300, bottom plate assembly; 310, bottom plate body; 311, supporting part; 320, second sealing member; 400, pole group; 500, insulating member. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or are the positions or positional relationships in which the inventive product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0047] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0050] Embodiment 1

[0051] like Figure 1-Figure 4As shown, this embodiment provides a columnar battery cell, which includes a shell 100, a cover plate assembly 200 and a bottom plate assembly 300. The shell 100 includes an inner shell 110 and an outer shell 120, the inner shell 110 is cylindrical and has a first opening and a second opening at opposite ends along a first direction, the outer shell 120 is a polygonal column, and the outer shell 120 is sleeved outside the inner shell 110. The first direction is the axial direction of the inner shell 110 and the outer shell 120. The cover plate assembly 200 is connected to one end of the inner shell 110 with a first opening, and blocks the first opening of the inner shell 110. The bottom plate assembly 300 is connected to one end of the housing 100 with a second opening, and the inner housing 110, the cover plate assembly 200 and the bottom plate assembly 300 are surrounded to form a first accommodation space 1101, and the first accommodation space 1101 is used to install the pole group 400, and the inner housing 110, the outer housing 120 and the bottom plate assembly 300 are surrounded to form a second accommodation space, and the second accommodation space is used to fill the phase change material. The first accommodation space 1101 and the second accommodation space are independent of each other and are not connected to each other.

[0052] When the temperature of the pole group 400 is high or low, the phase change material in the second accommodation space can absorb or release heat to keep the pole group 400 at a better working environment temperature, which is beneficial to extend the service life of the columnar battery cell and has good thermal management capabilities. In addition, the absorption of heat by the phase change material can also alleviate the risk of thermal runaway and heat spread in the columnar battery cell, and the safety performance of the columnar battery cell is relatively high. And because the second accommodation space is arranged around the circumference of the first accommodation space 1101, the heat can be evenly dissipated around the pole group 400, the thermal management effect is good, and the temperature uniformity of the pole group 400 is good.

[0053] Optionally, in this embodiment, the total volume of the phase change material injected into the second accommodation space when it is in liquid state is V1, the total volume of the second accommodation space is V, and V1 and V satisfy: 0.5≤V1 / V≤0.95. For example, the value of V1 / V can be 0.5, 0.6, 0.7, 0.8, 0.9 or 0.95, etc. By limiting the value of V1 / V within the above range, on the one hand, it is ensured that the amount of phase change material is sufficient, and during the recycling process of the columnar battery cell, the phase change material can completely absorb the heat generated when the pole group 400 is heated, so that the temperature of the pole group 400 is maintained between 10°C and 45°C, and the working temperature of the columnar battery cell is suitable, which is conducive to extending the service life; on the other hand, when the phase change material is injected into the second accommodation space, it will not overflow, and it is conducive to ensuring that the sealing of the second accommodation space is good. Otherwise, when the value of V1 / V is too small, the amount of phase change material is insufficient, the heat absorption effect of the phase change material on the pole group 400 is not obvious, and the thermal management effect is poor. Of course, the value of V1 / V should not be too large, otherwise there will be too much phase change material in the second storage space. When the phase change material undergoes phase change after absorbing heat, the pressure in the second storage space will be too high, which is not conducive to sealing. Moreover, when the phase change material in the second storage space is too full, it is not easy to encapsulate, which affects the sealing effect of the second storage space.

[0054] Optionally, the value range of V1 is 2000mm 3 ≤V1≤190000mm 3 , the value range of V is 4000mm 3 ≤V≤200000mm 3 For example, when the value of V is 4000mm 3 When V1 is 2000mm 3 、2400mm 3 、2800mm 3 、3200mm 3 or 3800mm 3 When the value of S is 200000mm 3 When S1 is 100000mm 3 、120000mm 3 、140000mm 3 、160000mm 3 or 190000mm 3 wait.

[0055] In addition, since the housing 120 in this embodiment is in a polygonal column shape, when a plurality of columnar cells are grouped to form a battery unit, the outer wall surfaces of two adjacent columnar cells can fit together, thereby improving space utilization and avoiding space waste. In addition, the outer wall surfaces of two adjacent columnar cells fit together, which can also play a limiting effect, the fixing effect of the columnar cells is good, and the integration, stability and reliability of the battery unit are relatively good.

[0056] As an optional solution, in this embodiment, the housing 120 is illustrated as a hexagonal prism. The phase change material can be one of paraffin, fatty acid, polyolefin and alcohol.

[0057] Continue to see Figure 2-Figure 4 The outer shell 120 in this embodiment includes n side plates 121 (n≥3), where n=6. The six side plates 121 are connected in sequence, each of which is in the shape of a flat plate. Each of the side plates 121 is tangent to the outer wall of the inner shell 110. The contact points between the side plates 121 and the outer wall of the inner shell 110 form a linear connecting portion 122. The connecting portion 122 extends along the first direction. The second accommodating space is divided into six subspaces 1201 by the connecting portion 122. An equal amount of phase change material is provided in each subspace 1201, that is, each subspace 1201 is injected with a phase change material with a volume of V1 / n, which is V1 / 6 here. Therefore, the phase change materials in each subspace 1201 will not affect each other, and the phase change materials in each subspace 1201 can independently adjust the temperature of the pole group 400 in the adjacent area, so as to perform targeted heat absorption or heat release. Moreover, the phase change materials in the separately arranged subspace 1201 can make the pole group 400 absorb or dissipate heat uniformly in the circumferential direction, and the pole group 400 has better temperature uniformity, which is beneficial to extending the service life of the columnar battery cell.

[0058] Optionally, in this embodiment, the inner shell 110 and the outer shell 120 can be made of metal materials, and the inner shell 110 and the outer shell 120 can be integrally formed. The inner shell 110 and the cover plate assembly 200 can be connected by welding.

[0059] Further, in this embodiment, the total cross-sectional area of ​​all subspaces 1201 in the cross section perpendicular to the first direction is S1, and the cross-sectional area of ​​each subspace 1201 in the cross section perpendicular to the first direction is S1 / n, that is, S1 / 6 here. The cross-sectional area of ​​the shell 100 in the cross section perpendicular to the first direction is S2, S=S1+S2. S1 and S satisfy: 0.5≤S1 / S≤0.9. For example, the value of S1 / S can be 0.5, 0.6, 0.7, 0.8 or 0.9, etc. By limiting the value of S1 / S within the above range, it is ensured that the cross-sectional area of ​​each subspace 1201 in the cross section perpendicular to the first direction is appropriate. On the one hand, the weight of the shell 100 is not too heavy, and the mass density of the columnar battery core is high; on the other hand, the molding yield of the shell 100 is high, the phase change material is easy to be injected into the subspace 1201, and the occupied area of ​​the subspace 1201 is small, and the volume energy density of the columnar battery core is high. It should be noted that the cross-sectional area of ​​the shell 100 in the section perpendicular to the first direction is equal to the sum of the cross-sectional areas of all side panels 121 in the section perpendicular to the first direction and the cross-sectional area of ​​the inner shell 110 in the section perpendicular to the first direction.

[0060] Optionally, the value range of S1 is 25mm 2 ≤S1≤900mm 2 , the value range of S is 50mm 2 ≤S≤1000mm 2 For example, when the value of S is 50mm 2 When S1 is 25 mm 2 , 30mm 2 、35mm 2 , 40mm 2 , or 45mm 2 When the value of S is 1000mm 2 When S1 is 500 mm 2 、600mm 2 、700mm 2 , 800mm 2 or 900mm 2 wait.

[0061] See also Figure 5 , Figure 7 and Figure 8 The housing 100 in this embodiment includes six first sealing members 130. The first sealing member 130 in each subspace 1201 is used to block a first opening of the subspace 1201 close to one end of the cover plate assembly 200 along the first direction. The first opening is sealed by the first sealing member 130. The first sealing member 130 can be connected to the inner shell 110 and the outer shell 120 by welding, so as to ensure good sealing of each subspace 1201.

[0062] Exemplarily, the first sealing member 130 in this embodiment includes an end plate 131, a first sealing plate 132, a second sealing plate 133 and a third sealing plate 134. The first sealing plate 132, the second sealing plate 133 and the third sealing plate 134 are all connected to one side of the end plate 131 along the first direction. The first sealing plate 132, the second sealing plate 133, the third sealing plate 134 and the end plate 131 form a receiving groove 1301. The receiving groove 1301 is connected to the subspace 1201. The first sealing plate 132 and the second sealing plate 133 are flat plates. The first sealing plate 132 and the second sealing plate 133 are respectively attached to the inner wall surface of a side plate 121. The third sealing plate 134 is an arc-shaped plate, and the curvature of the third sealing plate 134 is consistent with the curvature of the outer wall surface of the inner shell 110. The third sealing plate 134 is attached to the outer wall surface of the inner shell 110, thereby sealing the first opening through the first sealing member 130. Furthermore, by providing the receiving groove 1301 , the phase change material in the subspace 1201 can also diffuse to the receiving groove 1301 , thereby increasing the volume of the subspace 1201 and being able to fill more phase change material, so as to improve the thermal management effect.

[0063] Furthermore, the side where the end plate 131 is connected to the first sealing plate 132 and the second sealing plate 133 extends in a direction away from the inner shell 110 to form a lap joint 1311, and the lap joint 1311 abuts against the end of the side plate 121 along the first direction, and the end of the lap joint 1311 away from the end plate 131 is flush with the outer wall surface of the side plate 121, and then the lap joint 1311 and the side plate 121 can be welded at the joint, so as to achieve fixation, and the appearance of the columnar battery cell is relatively smooth, without protruding parts, to avoid scratching adjacent columnar battery cells when grouping. In addition, the setting of the lap joint 1311 also facilitates the limiting of the first sealing member 130, and the assembly is relatively easy, with a high assembly qualification rate and high assembly precision.

[0064] See also Figure 6-Figure 8In this embodiment, the bottom plate assembly 300 is separately provided from the housing 100. The bottom plate assembly 300 includes a bottom plate body 310 and six second sealing members 320. The bottom plate body 310 is connected to one end of the inner shell 110 provided with a second opening and blocks the second opening. The number of the second sealing members 320 is the same as that of the first sealing members 130 and the subspaces 1201 and they correspond one to one. The second sealing members 320 in each subspace 1201 are used to block the second opening of the subspace 1201 away from the cover plate assembly 200 along the first direction. The first accommodation space 1101 is formed into a closed space by the bottom plate body 310, the inner shell 110 and the cover plate assembly 200. Each subspace 1201 of the second accommodation space is formed into a closed space by the first sealing member 130, the second sealing member 320, the inner shell 110 and the outer shell 120, thereby ensuring good sealing of the first accommodation space 1101 and each subspace 1201 of the second accommodation space.

[0065] Optionally, the structure of the second sealant 320 can be the same as that of the first sealant 130, thereby reducing the types of structural parts of the columnar battery cell, making parts processing easier, and assembling more convenient and quicker. There are relatively fewer assembly stations on the production line, and the first sealant 130 and the second sealant 320 do not need to be separately set up at assembly stations, and can share one assembly station.

[0066] Furthermore, a support portion 311 may be provided on one side of the bottom plate body 310 facing the first accommodating space 1101, and the electrode group 400 may be supported by the support portion 311, thereby ensuring that the electrode group 400 is well fixed in the first accommodating space 1101, is not prone to shaking, and the risk of short circuit is reduced, thereby increasing the reliability and safety of the columnar battery cell.

[0067] Continue to see Figure 1 and Figure 5 The cover plate assembly 200 in this embodiment includes a cover plate body 210 and a pole 220. The cover plate body 210 is connected to one end of the inner shell 110 having a first opening and blocks the first opening. The positive pole of the pole group 400 is electrically connected to the pole 220, and the negative pole of the pole group 400 is electrically connected to the shell 100, thereby leading out the pole group 400 so that the columnar battery cell can be charged and discharged externally. Alternatively, in some embodiments, the negative pole of the pole group 400 may also be electrically connected to the bottom plate body 310. Furthermore, the cover plate assembly 200 also includes an insulating member 500, which is sandwiched between the cover plate body 210 and the pole group 400, and the cover plate body 210 is insulated and isolated from the pole group 400 by the insulating member 500, thereby avoiding the risk of short circuit.

[0068] The following is a cycle test of the columnar battery cell with the above structure using samples of different design sizes to examine the effect of the parameter V1 / V on the performance of the columnar battery cell. The results are shown in Table 1.

[0069] Table 1

[0070]

[0071] From the above results, it can be concluded that in sample 1, the value of V1 / V is less than the minimum value of 0.5≤V1 / V≤0.95. At this time, the volume of the phase change material in each subspace 1201 is small, the heat absorption and cooling effect on the electrode group 400 is not obvious, the thermal management effect is poor, the service life of the columnar battery cell is short, and the product is defective.

[0072] In samples 2 to 12, the value of V1 / V satisfies the value range restriction of 0.5≤V1 / V≤0.95. When the first seal 130 is assembled with the shell 100, the phase change material injected into the subspace 1201 will not overflow, and after the first seal 130 is assembled with the shell 100, the phase change material will not spread due to the siphon effect. The sealing effect between the first seal 130 and the shell 100 is good, and the problem of phase change material leakage is not likely to occur. In addition, during the recycling of the columnar battery cell, the phase change material has a significant heat absorption and cooling effect on the pole group 400. The temperature of the pole group 400 is maintained between 10°C and 45°C, the working temperature is relatively suitable, the service life of the columnar battery cell is long, and the product is good.

[0073] In sample 13, the value of V1 / V is greater than the maximum value of 0.5≤V1 / V≤0.95. At this time, the volume of the phase change material in each subspace 1201 is too large. When the first seal 130 is assembled with the shell 100, the phase change material injected into the subspace 1201 is prone to overflow (with a probability greater than 5%). After the first seal 130 is assembled with the shell 100, the phase change material will spread due to the siphon effect, and the sealing effect between the first seal 130 and the shell 100 is poor. The phase change material is prone to leak, resulting in a defective product.

[0074] The columnar cells of the above structure are assembled with samples of different design sizes to investigate the effect of the parameter S1 / S on the performance of the columnar cells. The results are shown in Table 2.

[0075] Table 2

[0076]

[0077] From the above results, it can be concluded that in sample 1, the value of S1 / S is less than the minimum value of 0.5≤S1 / S≤0.9. At this time, the cross-sectional area of ​​each subspace 1201 in the section perpendicular to the first direction is small, which is inconvenient for liquid injection, and the weight of the shell 100 is large, which is not conducive to the improvement of the mass density of the columnar battery cell, resulting in a defective product.

[0078] In samples 2 to 12, the value of S1 / S satisfies the value range restriction of 0.5≤S1 / S≤0.9, and the phase change material is easily injected into the subspace 1201 without overflowing. In addition, the molding yield of the housing 100 is high, the weight is light, the mass density and volume energy density of the columnar battery cell are both high, and the product is good.

[0079] In sample 13, the value of S1 / S is greater than the maximum value of 0.5≤S1 / S≤0.9. At this time, the phase change material is easily injected into the subspace 1201, but the cross-sectional area of ​​each subspace 1201 accounts for a large proportion, the shell 100 is not easy to form, and it is not conducive to the improvement of the volume energy density of the columnar battery cell, resulting in a defective product.

[0080] This embodiment also provides a power battery, including a battery box and at least one battery cell, the battery cell is arranged in the battery box, and each battery cell includes a plurality of columnar cells. By adopting the columnar cells in this embodiment, when a plurality of columnar cells are grouped, adjacent columnar cells can fit each other, or be arranged at a small interval, which is conducive to improving the space utilization rate of the battery cell in the battery box and making rational use of the space. At the same time, the columnar cells themselves have good thermal management capabilities, and the columnar cells can be charged and discharged at the optimal working environment temperature. The power battery has excellent performance and a long service life.

[0081] Embodiment 2

[0082] This embodiment also provides a cylindrical battery cell, see Fig. 9 and Fig.10 The difference between the cylindrical battery cell and the first embodiment is that the bottom plate assembly 300 and the housing 100 are integrally formed, which shortens the time spent on assembly and improves the assembly efficiency.

[0083] Optionally, the bottom plate assembly 300 in this embodiment includes a bottom plate body 310, which is in a flat plate shape, and the shape of the cross section of the bottom plate body 310 is consistent with the shape of the cross section of the outer shell 120, the circumferential edge of the bottom plate body 310 is connected to the outer shell 120, and the end of the inner shell 110 is connected to the wall of the bottom plate body 310 facing the first accommodation space 1101. The second opening of the inner shell 110 can be blocked by the bottom plate body 310, and the second opening of each subspace 1201 along the first direction away from the cover plate assembly 200 is blocked. In this way, the first accommodation space 1101 surrounded by the bottom plate body 310, the inner shell 110 and the cover plate assembly 200 is a closed space, and each subspace 1201 of the second accommodation space surrounded by the bottom plate body 310, the first sealing member 130, the inner shell 110 and the outer shell 120 is a closed space, and the sealing performance of each subspace 1201 of the first accommodation space 1101 and the second accommodation space is good.

[0084] This embodiment also provides a power battery, including a battery box and at least one battery cell, the battery cell is arranged in the battery box, and each battery cell includes a plurality of columnar cells. By adopting the columnar cells in this embodiment, when a plurality of columnar cells are grouped, adjacent columnar cells can fit each other, or be arranged at a small interval, which is conducive to improving the space utilization rate of the battery cell in the battery box and making rational use of the space. At the same time, the columnar cells themselves have good thermal management capabilities, and the columnar cells can be charged and discharged at the optimal working environment temperature. The power battery has excellent performance and a long service life.

[0085] The remaining structures in this embodiment are the same as those in the first embodiment and will not be described again here.

[0086] Embodiment 3

[0087] This embodiment also provides a cylindrical battery cell, see Figure 11-13 The difference between the cylindrical battery cell in the first embodiment and the outer shell 120 in the present embodiment is that the outer shell 120 is a quadrangular prism, and the outer shell 120 includes four side plates 121 connected in sequence, and the side plates 121 are flat, and each side plate 121 is tangent to the outer wall surface of the inner shell 110, and the contact point between the side plate 121 and the outer wall surface of the inner shell 110 forms a linear connection portion 122, and the connection portion 122 extends along the first direction. The second accommodating space is divided into four subspaces 1201 by the connection portion 122, and each subspace 1201 is provided with an equal amount of phase change material.

[0088] Therefore, the phase change materials in each subspace 1201 will not affect each other. The phase change materials in each subspace 1201 can independently adjust the temperature of the electrode group 400 in the adjacent area, thereby absorbing or releasing heat in a targeted manner. The temperature uniformity of the electrode group 400 is better, which is beneficial to extending the service life of the columnar battery cell.

[0089] Optionally, in this embodiment, the number of the first sealing member 130 and the number of the second sealing member 320 are both four, so as to ensure that each subspace 1201 is well sealed to avoid leakage of the phase change material.

[0090] Of course, in other embodiments, according to the shape of the columnar battery cell, the housing 120 may also be configured as one of an octagonal prism, a decagonal prism or a dodecaprism, which are not listed here one by one. As long as the number of the first sealing member 130 and the second sealing member 320 is consistent with the number of the subspaces 1201, it is sufficient.

[0091] This embodiment also provides a power battery, including a battery box and at least one battery cell, the battery cell is arranged in the battery box, and each battery cell includes a plurality of columnar cells. By adopting the columnar cells in this embodiment, when a plurality of columnar cells are grouped, adjacent columnar cells can fit each other, or be arranged at a small interval, which is conducive to improving the space utilization rate of the battery cell in the battery box and making rational use of the space. At the same time, the columnar cells themselves have good thermal management capabilities, and the columnar cells can be charged and discharged at the optimal working environment temperature. The power battery has excellent performance and a long service life.

[0092] The remaining structures in this embodiment are the same as those in the first embodiment and will not be described again here.

[0093] Embodiment 4

[0094] This embodiment also provides a cylindrical battery cell, see Fig.14 and Fig.15 The difference between the cylindrical battery cell in the first embodiment and the outer shell 120 in the present embodiment is that the outer shell 120 is a quadrangular prism, and the outer shell 120 includes four side plates 121 connected in sequence, and the side plates 121 are flat, and each side plate 121 is tangent to the outer wall surface of the inner shell 110, and the contact point between the side plate 121 and the outer wall surface of the inner shell 110 forms a linear connection portion 122, and the connection portion 122 extends along the first direction. The second accommodating space is divided into four subspaces 1201 by the connection portion 122, and each subspace 1201 is provided with an equal amount of phase change material.

[0095] Therefore, the phase change materials in each subspace 1201 will not affect each other. The phase change materials in each subspace 1201 can independently adjust the temperature of the electrode group 400 in the adjacent area, thereby absorbing or releasing heat in a targeted manner. The temperature uniformity of the electrode group 400 is better, which is beneficial to extending the service life of the columnar battery cell.

[0096] In addition, the bottom plate assembly 300 is integrally formed with the housing 100, which shortens the time spent on assembly and has high assembly efficiency. The bottom plate assembly 300 includes a bottom plate body 310, which is in the shape of a flat plate, and the shape of the cross section of the bottom plate body 310 is consistent with the shape of the cross section of the outer shell 120, the circumferential edge of the bottom plate body 310 is connected to the outer shell 120, and the end of the inner shell 110 is connected to the wall of the bottom plate body 310 facing the first accommodating space 1101. The second opening of the inner shell 110 can be blocked by the bottom plate body 310, and the second opening of each subspace 1201 along the first direction away from the cover plate assembly 200 is blocked. As a result, the first accommodating space 1101 surrounded by the base plate body 310, the inner shell 110 and the cover plate assembly 200 is a closed space, and each subspace 1201 of the second accommodating space surrounded by the base plate body 310, the first sealing component 130, the inner shell 110 and the outer shell 120 is a closed space, and the sealing properties of the first accommodating space 1101 and each subspace 1201 of the second accommodating space are good.

[0097] Optionally, in this embodiment, the number of the first sealing members 130 is four to ensure that each subspace 1201 is well sealed to prevent leakage of the phase change material.

[0098] Of course, in other embodiments, according to the shape of the columnar battery cell, the housing 120 may also be configured as one of an octagonal prism, a decagonal prism or a dodecaprism, which are not listed here one by one. As long as the number of the first sealing members 130 is consistent with the number of the subspaces 1201 , it is sufficient.

[0099] This embodiment also provides a power battery, including a battery box and at least one battery cell, the battery cell is arranged in the battery box, and each battery cell includes a plurality of columnar cells. By adopting the columnar cells in this embodiment, when a plurality of columnar cells are grouped, adjacent columnar cells can fit each other, or be arranged at a small interval, which is conducive to improving the space utilization rate of the battery cell in the battery box and making rational use of the space. At the same time, the columnar cells themselves have good thermal management capabilities, and the columnar cells can be charged and discharged at the optimal working environment temperature. The power battery has excellent performance and a long service life.

[0100] The remaining structures in this embodiment are the same as those in the first embodiment and will not be described again here.

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A cylindrical battery cell, characterized in that: include: The housing comprises an inner housing and an outer housing, wherein the inner housing is cylindrical and has a first opening and a second opening at two opposite ends along a first direction, and the outer housing is polygonal and is sleeved outside the inner housing; A cover plate assembly connected to one end of the inner shell provided with the first opening; A bottom plate assembly is connected to one end of the shell body provided with the second opening, the inner shell, the cover plate assembly and the bottom plate assembly are arranged to form a first accommodation space, the first accommodation space is used to install the pole group, the inner shell, the outer shell and the bottom plate assembly are arranged to form a second accommodation space, the second accommodation space is used to fill the phase change material; The total volume of the phase change material injected into the second accommodation space when it is in liquid state is V1, and the total volume of the second accommodation space is V; V1 and V satisfy the following condition: 0.5≤V1 / V≤0.

95.

2. The cylindrical battery cell according to claim 1, characterized in that: The outer shell includes a plurality of side plates connected in sequence, the side plates are in the shape of flat plates, and the side plates are tangent to the outer wall surface of the inner shell, and the contact points between the side plates and the outer wall surface of the inner shell form a straight-line connection portion, the connection portion extends along a first direction, and the connection portion divides the second accommodation space into a plurality of sub-spaces, and the phase change material is arranged in each of the sub-spaces; The total cross-sectional area of ​​all the subspaces is S1, and the cross-sectional area of ​​the shell is S2; S=S1+S2; S1 and S satisfy: 0.5≤S1 / S≤0.

9.

3. The cylindrical battery cell according to claim 2, characterized in that: The shell includes a plurality of first sealing members, and the first sealing member in each of the subspaces is used to seal a first opening of the subspace along a first direction close to one end of the cover plate assembly.

4. The cylindrical battery cell according to claim 3, characterized in that: The first sealing member includes an end plate, a first sealing plate, a second sealing plate and a third sealing plate, the first sealing plate, the second sealing plate and the third sealing plate are all connected to one side of the end plate along the first direction, the first sealing plate, the second sealing plate, the third sealing plate and the end plate form a receiving groove, the receiving groove is connected to the subspace, the first sealing plate and the second sealing plate are respectively attached to the inner wall surface of one of the side plates, and the third sealing plate is attached to the outer wall surface of the inner shell.

5. The cylindrical battery cell according to claim 4, characterized in that: One side of the end plate connected to the first sealing plate and the second sealing plate extends in a direction away from the inner shell to form a lap portion, the lap portion is connected to the end of the side plate along the first direction, and the end of the lap portion away from the end plate is flush with the outer wall surface of the side plate.

6. The cylindrical battery cell according to claim 4, characterized in that: The bottom plate assembly is separately arranged from the shell, and the bottom plate assembly includes a bottom plate body and a plurality of second sealing members. The bottom plate body is connected to one end of the inner shell where the second opening is provided and seals the second opening. The number of the second sealing members is the same as that of the first sealing members and the subspaces and they correspond one to one. The second sealing member in each subspace is used to seal the second opening of the subspace along the first direction away from the side of the cover plate assembly.

7. The cylindrical battery cell according to claim 6, characterized in that: The structure of the second sealing member is the same as that of the first sealing member.

8. The cylindrical battery cell according to claim 4, characterized in that: The bottom plate assembly is integrally formed with the shell, and comprises a bottom plate body, wherein the bottom plate body is used to block the second opening of the inner shell and block the second opening of each subspace on a side away from the cover plate assembly along the first direction.

9. The cylindrical battery cell according to any one of claims 1 to 8, characterized in that: The cover plate assembly includes a cover plate body and a pole, the cover plate body is connected to one end of the inner shell provided with the first opening and blocks the first opening, the positive electrode of the pole group is electrically connected to the pole, and the negative electrode of the pole group is electrically connected to the shell.

10. A power battery, characterized in that: It comprises a battery box and at least one battery cell, wherein the battery cell is arranged in the battery box, and each of the battery cells comprises a plurality of columnar battery cells according to any one of claims 1 to 9.

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