End plate and power battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses an end plate and a power battery, the end plate comprises a tab supporting area and two pole group supporting areas, the two pole group supporting areas are respectively arranged at two sides of the tab supporting area, and the end plate protrudes towards a direction deviating from a pole group along a midpoint of a first direction to form an arch structure. The injection-molded end plate is arranged to be of the arch structure protruding towards the side away from the pole group, and the pre-deformation amount is set in the length direction of the end plate in a regional gradient mode, so that reverse compensation is conducted on buckling deformation generated after the end plate is subjected to injection molding and cooling; the pre-deformation amount and the buckling deformation amount generated by the pole group supporting area of the end plate which is cooled and shaped after injection molding to the side where the cover plate is located are mutually offset, the flatness of the finally formed end plate is good, the end plate can effectively support the pole group and the pole lug, and it is guaranteed that the end plate and the protective insulating film of the pole group can be effectively fused and connected. The invention also provides a power battery which comprises the end plate.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to an end plate and a power battery. Background Art

[0002] A power battery generally includes a housing, a cover plate, a pole group, and an end plate. An opening is provided on the housing. The pole group passes through the opening and is arranged inside the housing. The cover plate is encapsulated at the opening of the housing. The end plate is arranged between the cover plate and the pole group. The pole tabs of the pole group pass through the end plate and are connected to the pole posts integrated on the cover plate. Support platforms are provided at both ends in the length direction of the end plate. The pole group and the cover plate can be supported through the support platforms to form a space for bending the pole tabs between the pole group and the cover plate. The support platforms are often of a hollow structure. On the one hand, it can reduce the weight of the end plate and the material cost. On the other hand, it can also form an exhaust passage, so that the gas generated inside the housing can act on the explosion-proof valve on the cover plate through the exhaust passage. When the internal pressure of the housing is too high, the pressure relief function can be realized to ensure safety.

[0003] However, the end plate is usually injection-molded from a plastic material. It has a relatively long length, a relatively thin wall thickness at the middle position in the length direction, and hollow support platforms are also provided at both ends in the length direction. Therefore, it is extremely easy to warp and deform after injection molding, which affects the fixation of the pole tabs and the pole posts. In severe cases, the pole tabs will be torn, resulting in the internal short-circuit failure of the power battery. In addition, the end plate also needs to be fused with the insulating film outside the pole group to form insulation between the pole group and the inner wall of the housing. After the end plate is deformed, it affects the fusion of the insulating film and the end plate, and will also lead to the internal short-circuit failure of the power battery, with low reliability. Summary of the Invention

[0004] The purpose of the present invention is to provide an end plate and a power battery. Before injection molding, a deformation amount is reserved in the opposite direction of the bending deformation of the end plate to compensate for the warping deformation generated after the subsequent injection molding and cooling of the end plate, so as to ensure good flatness of the end plate.

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

[0006] On the one hand, the present invention provides an end plate arranged on one side of a pole group. The midpoint of the end plate in the first direction protrudes in the direction away from the pole group. The end plate includes:

[0007] A pole tab support area and two pole group support areas. The two pole group support areas are respectively arranged on both sides of the pole tab support area in the first direction. The end plate in each pole group support area includes a support surface in contact with the pole group. The outer edges of the two support surfaces facing away from each other are both located in a reference plane;

[0008] The total length of the end plate along the first direction is L, and the thickness of the end plate along the second direction is H; along the second direction, the height of the end plate located at the midpoint of the pole lug support area relative to the reference plane toward the side away from the pole group is H0, H0=H+L / a;

[0009] Among them, the value range of a is 50≤a≤100;

[0010] The value range of L is 50mm≤L≤200mm;

[0011] The value range of H is 2mm≤H≤12mm.

[0012] Optionally, along the direction from the pole ear support area to the pole group support area, the height of the end plate located in the pole group support area that is arched relative to the reference plane toward the side away from the pole group gradually decreases, and the average height of the end plate located in the pole group support area that is arched relative to the reference plane toward the side away from the pole group is H2, H2=H+L / c;

[0013] Among them, the value range of c is 200≤c≤500.

[0014] Optionally, the end plate further comprises two safety reserved areas, which are respectively arranged on both sides of the pole lug support area, and each of the safety reserved areas is adjacent to one of the pole group support areas;

[0015] The average height of the end plate located in the safety reserved area arched toward the side away from the pole group relative to the reference plane is H1, H1=H+L / b;

[0016] Among them, the value range of b is 100≤b≤250.

[0017] Optionally, the end plate includes an end plate body, a first support platform and a second support platform, the end plate body is located in the pole ear support area, the first support platform and the second support platform are respectively located in one of the pole group support areas, and the first support platform and the second support platform both include the support surface, and the support surface is arranged toward the pole group.

[0018] Optionally, the end plate body includes a base plate, a first side plate and a second side plate, and both ends of the base plate, the first side plate and the second side plate along the first direction are connected to the first support platform and the second support platform, and the first side plate and the second side plate are respectively located on both sides of the base plate along the third direction, and a hollow portion is formed between at least one of the first side plate and the second side plate and the base plate, and the height of the midpoint of the length of the first side plate and the second side plate that is away from the pole group and arched toward the side away from the pole group relative to the reference plane is H0.

[0019] Optionally, the first support platform includes a first abutment plate, a third side plate, a fourth side plate and a fifth side plate, the end surface of the first abutment plate facing the pole group is the support surface, the third side plate is connected to the first side plate, the fourth side plate is connected to the second side plate, the fifth side plate is adjacent to and connected to the first abutment plate, the third side plate and the fourth side plate, and the average height of the ends of the third side plate and the fourth side plate facing away from the first abutment plate relative to the reference plane and arched toward the side facing away from the pole group is H2.

[0020] Optionally, the second support platform includes a second abutment plate, a sixth side plate, a seventh side plate and an eighth side plate, the end surface of the second abutment plate facing the pole group is the support surface, the sixth side plate is connected to the first side plate, the seventh side plate is connected to the second side plate, the eighth side plate is adjacent to and connected to the second abutment plate, the sixth side plate and the seventh side plate, and the average height of the ends of the sixth side plate and the seventh side plate facing away from the second abutment plate relative to the reference plane and arched toward the side facing away from the second abutment plate is H2.

[0021] Optionally, a length of the first support platform along the first direction is smaller than a length of the second support platform along the first direction.

[0022] Optionally, the first support platform is provided with weight-reducing holes, and the second support platform is provided with ventilation holes and weight-reducing grooves.

[0023] On the other hand, the present invention provides a power battery, comprising the end plate in any of the above solutions.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides an end plate, which includes a pole ear support area and two pole group support areas, the two pole group support areas are respectively arranged on both sides of the pole ear support area, and the midpoint of the end plate along the first direction protrudes in the direction away from the pole group to form an arched structure. By setting the injection-molded end plate as an arched structure protruding toward the side away from the pole group, and setting the pre-deformation amount by regional gradient in the length direction of the end plate, the warping deformation of the end plate after injection molding and cooling is reversely compensated, and the pre-deformation amount and the warping deformation of the pole group support area of the end plate after injection molding and cooling and shaping toward the side where the cover plate is located offset each other, and the end plate finally formed has good flatness, and the end plate can effectively support the pole group and the pole ear, and at the same time, the protective insulating film of the end plate and the pole group can be effectively fused and connected.

[0026] The present invention also provides a power battery, including the above-mentioned end plate. The flatness of the end plate after injection molding and cooling is relatively high. The end plate can be closely attached to the cover plate, playing a good supporting role for the pole group and the pole ear, avoiding the tearing of the pole ear, and having a good fixing effect on the pole ear and the pole group. Moreover, the end plate can also be effectively integrated with the insulating film outside the pole group, with a good fixing effect, and it is not easy to occur short-circuit failure inside the power battery, and the reliability and safety are high. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0028] Figure 1 It is a schematic structural diagram of the end plate provided in the embodiment of the present invention;

[0029] Figure 2 It is a top view of the end plate provided in the embodiment of the present invention;

[0030] Figure 3 It is a front view of the end plate provided in the embodiment of the present invention.

[0031] In the figure:

[0032] 10. End plate; 11. Pole ear support area; 12. Pole group support area; 13. Safety reserved area; 20. Reference plane; 110. End plate body; 1101. Hollow part; 111. Substrate; 112. First side plate; 113. Second side plate; 120. First support platform; 121. First abutting plate; 1211. Weight reduction hole; 122. Third side plate; 123. Fourth side plate; 124. Fifth side plate; 125. First connecting plate; 130. Second support platform; 131. Second abutting plate; 1311. Ventilation hole; 1312. Weight reduction groove; 132. Sixth side plate; 133. Seventh side plate; 134. Eighth side plate; 135. Second connecting plate. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following will clearly and completely describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0034] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and moreover, the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the first feature has a lower horizontal height than the second feature.

[0035] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation to the present invention.

[0037] As Figures 1 - 3 shown, this embodiment provides an end plate 10. The end plate 10 is disposed on one side of the electrode group, and the electrode group can be insulated from the cover plate through the end plate 10. The end plate 10 includes an ear support area 11 and two electrode group support areas 12. The two electrode group support areas 12 are respectively disposed on both sides of the ear support area 11. The midpoint of the end plate 10 along the first direction bulges towards the direction away from the electrode group to form an arched structure; the end plate 10 located in each electrode group support area 12 includes a support surface that abuts against the electrode group, and the outer edges of the two support surfaces facing away from each other are both located in the reference plane 20. Among them, the first direction refers to the length direction of the end plate 10, that is, Figure 1 the X-axis direction shown in

[0038] Generally speaking, the pole group support area 12 of the end plate 10 is often set as a hollow structure, and more material is placed here during the injection molding of the end plate 10, while the pole ear support area 11 of the end plate 10 has a thinner wall thickness and a longer length, and less material is placed here during the injection molding of the end plate 10. Therefore, after the end plate 10 is injection molded and cooled, the pole group support area 12 of the end plate 10 is prone to warping toward the side where the cover plate is located, resulting in poor flatness of the end plate 10. In this embodiment, the injection molded end plate 10 is set as an arched structure that bulges toward the side away from the pole group, and a pre-deformation amount is set in a regional gradient in the length direction of the end plate 10, thereby reversely compensating for the warping deformation that occurs after the injection molding and cooling of the end plate 10. The pole group support area 12 of the end plate 10 that is cooled and shaped after injection molding produces a warping deformation amount toward the side where the cover plate is located, and the pre-deformation amount and the warping deformation amount offset each other, so that the flatness of the final end plate 10 is good. It is ensured that the end plate 10 can play an effective supporting role on the pole group and the pole ear, and at the same time, it is ensured that the protective insulating film of the end plate 10 and the pole group can be effectively fused and connected.

[0039] It should be noted that the longer the total length of the end plate 10 is, the greater the warping deformation will be when it is cooled and finalized after injection molding. Therefore, there is a certain relationship between the pre-deformation of the end plate 10 and the total length of the end plate 10. According to the different functions of each part of the end plate 10, the end plate 10 is divided into a pole group support area 12, a pole ear support area 11 and a pole group support area 12 along the first direction. The warping deformation after injection molding and cooling is usually bent from the side with less material to the side with more material. Therefore, the pre-deformation is set on the side with relatively less material. Since there are pole group support areas 12 at both ends of the end plate 10, it can play a certain pulling effect on the end plate 10 as a whole. The warping deformation on both sides of the length direction of the end plate 10 is relatively small. Therefore, the closer to the middle position of the length direction of the end plate 10, the greater the pre-deformation of this position.

[0040] For example, the total length of the end plate 10 along the first direction is L, the thickness of the end plate 10 along the second direction is H, and the second direction is Figure 1 The Z-axis direction shown in . Along the second direction, the height of the end plate 10 located at the midpoint of the pole lug support area 11 that arches toward the side away from the pole group relative to the reference plane 20 is H0, H0=H+L / a. Among them, the value range of a is 50≤a≤100. For example, the value of a can be 50, 60, 70, 80, 90, 100. The pre-deformation amount set for the end plate 10 located at the midpoint of the pole lug support area 11 is H0-H. It should be noted that the closer to the midpoint of the length direction of the end plate 10, the greater the height of the end plate 10 located in the pole lug support area 11 that arches toward the side away from the pole group relative to the reference plane 20, and the height of the arch of the end plate 10 shows a gradual trend.

[0041] The value range of L is 50 mm ≤ L ≤ 200 mm. For example, in some embodiments, the value of L can be 50 mm, 80 mm, 100 mm, 120 mm, 150 mm, 200 mm, etc., and will not be listed one by one here. The value range of H is 2 mm ≤ H ≤ 12 mm. For example, in some embodiments, the value of H can be 2 mm, 5 mm, 8 mm, 10 mm, 12 mm, etc., and will not be listed one by one here.

[0042] Further, along the direction from the tab support area 11 to the cell group support area 12, the height at which the end plate 10 within the cell group support area 12 arches away from the cell group side relative to the reference plane 20 gradually decreases. The average height at which the end plate 10 within the cell group support area 12 arches away from the cell group side relative to the reference plane 20 is H2, and H2 = H + L / c. Among them, the value range of c is 200 ≤ c ≤ 500. For example, the value of c can be 200, 300, 400, 500, etc. The pre-deformation amount set for the end plate 10 in the cell group support area 12 is H2 - H.

[0043] It should be noted that the closer to the midpoint of the length direction of the end plate 10, the greater the height at which the end plate 10 within the cell group support area 12 arches away from the cell group side relative to the reference plane 20, and the height at which the end plate 10 arches shows a gradual change trend. And it should be noted that H2 < H0, that is, the height at which the end plate 10 within the cell group support area 12 arches away from the cell group side relative to the reference plane 20 is less than the height at which the end plate 10 within the tab support area 11 arches away from the cell group side relative to the reference plane 20.

[0044] Continue to refer to Figure 3 , the end plate 10 in this embodiment further includes two safety reserve areas 13, and the two safety reserve areas 13 are respectively arranged on both sides of the tab support area 11, and each safety reserve area 13 is adjacent to a cell group support area 12. The average height at which the end plate 10 within the safety reserve area 13 arches away from the cell group side relative to the reference plane 20 is H1, and H1 = H + L / b. Among them, the value range of b is 100 ≤ b ≤ 250. For example, the value of b can be 100, 150, 200, 250, etc. The pre-deformation amount set for the end plate 10 in the safety reserve area 13 is H1 - H. It should be noted that the closer to the midpoint of the length direction of the end plate 10, the greater the height at which the end plate 10 within the safety reserve area 13 arches away from the cell group side relative to the reference plane 20, and the height at which the end plate 10 arches shows a gradual change trend.

[0045] Moreover, in a specific embodiment, H2 < H1 < H0, that is, the average height of the end plate 10 located within the pole group support area 12 arching away from the pole group relative to the reference plane 20 is less than the average height of the end plate 10 located within the safety reserve area 13 arching away from the pole group relative to the reference plane 20. The average height of the end plate 10 located within the safety reserve area 13 arching away from the pole group relative to the reference plane 20 is less than the height of the end plate 10 at the midpoint of the tab support area 11 arching away from the pole group relative to the reference plane 20.

[0046] Continue to refer to Figure 1 and Figure 2 , the specific structure of the end plate 10 in this embodiment can adopt the following solution. The end plate 10 includes an end plate body 110, a first support platform 120, and a second support platform 130. The end plate body 110 is located within the tab support area 11 and the safety reserve area 13. The first support platform 120 and the second support platform 130 are respectively located within a pole group support area 12. Both the first support platform 120 and the second support platform 130 include a support surface, and the support surface faces the pole group.

[0047] Optionally, the end plate body 110 includes a base plate 111, a first side plate 112, and a second side plate 113. Both ends of the base plate 111, the first side plate 112, and the second side plate 113 in the first direction are connected to the first support platform 120 and the second support platform 130. The first side plate 112 and the second side plate 113 are respectively located on both sides of the base plate 111 in the third direction, where the third direction refers to the width direction of the end plate 10, that is, Figure 1 the Y-axis direction shown in

[0048] Further, the first support platform 120 includes a first abutment plate 121, a third side plate 122, a fourth side plate 123 and a fifth side plate 124. The end surface of the first abutment plate 121 facing the pole group is a support surface, and the pole group can be supported by the first abutment plate 121. The third side plate 122 is connected to the first side plate 112, and the third side plate 122 and the first side plate 112 are located in the same plane. The fourth side plate 123 is connected to the second side plate 113, and the fourth side plate 123 and the second side plate 113 are located in the same plane. The fifth side plate 124 is adjacent to and connected to the first abutment plate 121, the third side plate 122, and the fourth side plate 123, and the fifth side plate 124 is located at the end of the length direction of the end plate 10. The first abutment plate 121 can be supported by the third side plate 122, the fourth side plate 123 and the fifth side plate 124, so that the first abutment plate 121 can well support the pole group, and play a good fixing effect on the pole group. The ends of the third side plate 122 and the fourth side plate 123 that are away from the first contact plate 121 are arched toward the side away from the pole group relative to the reference plane 20 by an average height H2.

[0049] Optionally, the first support platform 120 also includes a first connecting plate 125, and the two ends of the first connecting plate 125 are respectively connected to the first abutment plate 121 and the substrate 111. The first connecting plate 125 can improve the connection strength between the first support platform 120 and the end plate body 110, and the end plate 10 supports the pole group more stably. The structural strength of the end plate 10 itself is also relatively high, and deformation problems are not likely to occur during subsequent use.

[0050] In addition, a plurality of weight-reducing holes 1211 are provided on the first abutting plate 121 of the first supporting platform 120, and the plurality of weight-reducing holes 1211 are arranged at intervals on the first abutting plate 121. By providing the weight-reducing holes 1211, the amount of material used in making the end plate 10 can be reduced, the cost can be reduced, and the total weight of the power battery can be reduced, which is conducive to achieving lightweight power batteries.

[0051] Continue to see Figure 1 and Figure 2The second support platform 130 includes a second abutment plate 131, a sixth side plate 132, a seventh side plate 133 and an eighth side plate 134. The end surface of the second abutment plate 131 facing the pole group is a support surface, and the pole group can also be supported by the second abutment plate 131. The sixth side plate 132 is connected to the first side plate 112, and the sixth side plate 132 and the first side plate 112 are located in the same plane. The seventh side plate 133 is connected to the second side plate 113, and the seventh side plate 133 and the second side plate 113 are located in the same plane. The eighth side plate 134 is adjacent to and connected to the second abutment plate 131, the sixth side plate 132, and the seventh side plate 133. The eighth side plate 134 is located at the end of the length direction of the end plate 10. The second abutment plate 131 can be supported by the sixth side plate 132, the seventh side plate 133 and the eighth side plate 134, so that the second abutment plate 131 can well support the pole group, and has a good fixing effect on the pole group. The average height of the ends of the sixth side plate 132 and the seventh side plate 133 that are away from the second abutting plate 131 and that are arched toward the side away from the second abutting plate 131 relative to the reference plane 20 is H2.

[0052] Optionally, the second support platform 130 also includes a second connecting plate 135, and the two ends of the second connecting plate 135 are respectively connected to the second abutment plate 131 and the substrate 111. The second connecting plate 135 can improve the connection strength between the second support platform 130 and the end plate body 110, and the end plate 10 supports the pole group more stably. The structural strength of the end plate 10 itself is also relatively high, and deformation problems are not likely to occur during subsequent use.

[0053] In addition, a plurality of ventilation holes 1311 may be provided on the second abutment plate 131 of the second support platform 130. The plurality of ventilation holes 1311 are arranged at intervals on the second abutment plate 131. The ventilation holes 1311 can connect the internal space of the power battery with the exhaust channel of the explosion-proof valve integrated on the cover plate to achieve a pressure relief function when the air pressure inside the power battery is too high, thereby ensuring the safety of the power battery.

[0054] Furthermore, the length of the first support platform 120 along the first direction can be set to be smaller than the length of the second support platform 130 along the first direction. More vents 1311 are provided on the second abutting plate 131 to improve exhaust efficiency, and at the same time, the ventilation volume of the vents 1311 can be matched with the exhaust volume of the explosion-proof valve, thereby improving exhaust smoothness, accelerating exhaust efficiency, and improving safety.

[0055] Optionally, in some embodiments, a plurality of weight-reducing grooves 1312 are provided on the sixth side plate 132 and the seventh side plate 133 of the second support platform 130, the weight-reducing grooves 1312 are provided on the side away from the pole group, and the plurality of weight-reducing grooves 1312 are arranged at intervals on the sixth side plate 132 and the seventh side plate 133. By providing the weight-reducing grooves 1312, the amount of material used in making the end plate 10 can be further reduced, the cost can be reduced, and the total weight of the power battery can be reduced, which is conducive to achieving lightweight power batteries.

[0056] This embodiment also provides a power battery, including a shell, a cover plate, a pole group and the above-mentioned end plate 10. An opening is provided on one side of the shell, and the pole group and the end plate 10 are installed in the shell through the opening, and the end plate 10 is fixed to the insulating film of the pole group by hot melting. The cover plate is buckled at the opening of the shell and welded to the shell, and the pole group is enclosed in a closed space by the cover plate and the shell. The end plate 10 is arranged between the pole group and the cover plate, and the pole group can be insulated from the cover plate by the end plate 10. By adopting the end plate 10 in this embodiment, it can be ensured that the flatness of the end plate 10 after injection molding and cooling is good, and the end plate 10 can fit closely with the cover plate to play a good supporting role for the pole group and the pole ear, avoid the pole ear from being torn, and the fixing effect of the pole ear and the pole group is good. In addition, the end plate 10 can also be well fixed to the insulating film outside the pole group, and short circuit failure is not easy to occur inside the power battery, and the reliability and safety of the power battery are high.

[0057] Furthermore, an explosion-proof valve is provided at one end of the cover plate in the length direction (i.e., the first direction), and the explosion-proof valve is opposite to the second support platform 130 of the end plate 10 along the second direction. The vent hole 1311 on the second support platform 130 connects the exhaust channel of the explosion-proof valve with the internal space of the shell, so that the power battery can realize the pressure relief function.

[0058] Injection molding tests are performed on samples of the end plates 10 in some specific implementation schemes to explore the effects of the values of H0, H1, and H2 on the flatness of the end plates 10 after cooling and molding. The injection molding tests are divided into three groups, each group including ten samples of the end plates 10. In each group, the total length L of the end plates 10 along the first direction is equal, and the thickness H of the end plates 10 along the second direction is equal. The total length L of the end plates 10 along the first direction in different groups is different, and the thickness H of the end plates 10 along the second direction is different.

[0059] In the first group of injection molding tests, the value of the total length L of Samples 1 to 10 in the first direction was 88 mm, and the value of the thickness H of the end plate 10 in the second direction was 6 mm. Samples 1 to 5 adopted the scheme of setting the pre-deformation amount in this embodiment. Substituting into the calculation formulas of H0, H1, and H2, the value range of H0 of the end plate 10 in this group was 6.88 mm - 7.76 mm, the value range of H1 was 6.35 mm - 6.88 mm, and the value range of H2 was 6.18 mm - 6.44 mm. Samples 6 to 10 adopted the traditional design scheme of the end plate 10 without setting the pre-deformation amount. The injection molding results of Samples 1 to 10 are shown in Table 1.

[0060] Table 1

[0061]

[0062] In Samples 1 to 5, after injection molding and cooling, the values of H0, H1, and H2 were all close to 6 mm, and the values of H0 - H, H1 - H, and H2 - H approached 0 mm, indicating that each area of the end plate 10 after injection molding and cooling would rebound, and the rebound amounts of each area were different. Finally, the pre-deformation amounts set in advance for each area of the end plate 10 offset the warpage deformation amounts generated after injection molding and cooling of the end plate 10. The values of H0, H1, and H2 of the end plate 10 were all consistent with the thickness H of the end plate 10. After molding, the end plate 10 had almost no arching, and the flatness of the end plate 10 was good.

[0063] In Samples 6 to 10, no pre-deformation amount was set for the end plate 10 before injection molding and cooling. The values of H0, H1, and H2 were close to the thickness H of the end plate 10. After injection molding and cooling, the values of H0, H1, and H2 were quite different from the value of the thickness H of the end plate 10. The values of H0 - H, H1 - H, and H2 - H were all large, and even the value of H0 - H would exceed 1 mm, indicating that each area of the end plate 10 after injection molding and cooling would rebound. Finally, different degrees of warpage deformation amounts were generated in each area of the end plate 10, and the flatness of the end plate 10 was poor.

[0064] In the second group of injection molding tests, the value of the total length L of Samples 11 to 20 in the first direction was 50 mm, and the value of the thickness H of the end plate 10 in the second direction was 2 mm. Samples 11 to 15 adopted the scheme of setting the pre-deformation amount in this embodiment. Substituting into the calculation formulas of H0, H1, and H2, the value range of H0 of the end plate 10 in this group was 2.50 mm - 3.00 mm, the value range of H1 was 2.20 mm - 2.50 mm, and the value range of H2 was 2.10 mm - 2.25 mm. Samples 16 to 20 adopted the traditional design scheme of the end plate 10 without setting the pre-deformation amount. The injection molding results of Samples 11 to 20 are shown in Table 2.

[0065] Table 2

[0066]

[0067] Among Samples 11 to 15, the values of H0, H1, and H2 after injection molding and cooling are all very close to 2 mm. That is, the values of H0 - H, H1 - H, and H2 - H approach 0 mm, indicating that each area of the end plate 10 after injection molding and cooling will rebound, and the rebound amounts of each area are different. Eventually, the pre - deformation amounts set in advance for each area of the end plate 10 cancel out the warping deformation amounts generated after the end plate 10 is injection - molded and cooled. The values of H0, H1, and H2 of the end plate 10 are all consistent with the thickness H of the end plate 10. After molding, the end plate 10 has almost no arching, and the flatness of the end plate 10 is good.

[0068] Among Samples 16 to 20, no pre - deformation amount was set for the end plate 10 before injection molding and cooling. The values of H0, H1, and H2 are close to the thickness H of the end plate 10. After injection molding and cooling, the values of H0, H1, and H2 are quite different from the value of the thickness H of the end plate 10. The values of H0 - H, H1 - H, and H2 - H are all large. Even the value of H0 - H is close to 1 mm, indicating that each area of the end plate 10 after injection molding and cooling will rebound. Eventually, different degrees of warping deformation amounts are generated in each area of the end plate 10, and the flatness of the end plate 10 is not good.

[0069] In the third group of tests on injection molding, the total length L values of Samples 21 to 30 along the first direction are all 200 mm, and the thickness H values of the end plate 10 along the second direction are all 12 mm. Samples 21 to 25 adopt the scheme of setting pre - deformation amounts in this embodiment. Substituting into the calculation formulas of H0, H1, and H2, the value range of H0 of the end plate 10 in this group is 14.00 mm - 16.00 mm, the value range of H1 is 12.80 mm - 14.00 mm, and the value range of H2 is 12.40 mm - 12.80 mm. Samples 26 to 30 adopt the traditional design scheme of the end plate 10 without setting pre - deformation amounts. The results of the injection molding of Samples 21 to 30 are shown in Table 3.

[0070] Table 3

[0071]

[0072] Among Samples 21 to 25, the values of H0, H1, and H2 after injection molding and cooling are all very close to 12 mm. That is, the values of H0 - H, H1 - H, and H2 - H approach 0 mm, indicating that each area of the end plate 10 after injection molding and cooling will rebound, and the rebound amounts of each area are different. Eventually, the pre - deformation amounts set in advance for each area of the end plate 10 cancel out the warping deformation amounts generated after the end plate 10 is injection - molded and cooled. The values of H0, H1, and H2 of the end plate 10 are all consistent with the thickness H of the end plate 10. After molding, the end plate 10 has almost no arching, and the flatness of the end plate 10 is good.

[0073] Among Samples 26 to 30, no pre-deformation amount was set for the injection-molded cooling front end plate 10. The values of H0, H1, and H2 were close to the thickness H of the end plate 10. After injection molding and cooling, the values of H0, H1, and H2 differed significantly from the thickness H value of the end plate 10. The values of H0 - H, H1 - H, and H2 - H were all large, and even the value of H0 - H was close to 4 mm, indicating that each area of the end plate 10 after injection molding and cooling would rebound, and finally different degrees of warpage deformation amounts were generated in each area of the end plate 10, and the flatness of the end plate 10 was poor.

[0074] In summary, it shows that when the end plate 10 adopts the scheme of setting the pre-deformation amount in this embodiment, the warpage deformation that occurs after injection molding and cooling of the end plate 10 can be significantly offset, and the flatness of the end plate 10 after injection molding and cooling is good.

[0075] Obviously, the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments here. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

[0076] Note that in the description of this specification, the description with reference to terms such as "some embodiments" and "other embodiments" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

Claims

1. An end plate is provided on one side of the electrode group, characterized in that The midpoint of the end plate along the first direction protrudes away from the electrode group, and the end plate includes: a tab support area and two electrode group support areas, the two electrode group support areas are respectively arranged on both sides of the tab support area along the first direction; the end plate located in each electrode group support area includes a support surface in contact with the electrode group, and the outer edges of the two support surfaces facing away from each other are located in the reference plane; The total length of the end plate along the first direction is L, and the thickness of the end plate along the second direction is H; along the second direction, the height of the end plate at the midpoint of the tab support area arching away from the electrode group side relative to the reference plane is H0, H0 = H + L / a; Wherein, the value range of a is 50 ≤ a ≤ 100; The value range of L is 50mm ≤ L ≤ 200mm; The value range of H is 2mm ≤ H ≤ 12mm.

2. The end plate according to claim 1, characterized in that, Along the direction from the tab support area to the electrode group support area, the height of the end plate located in the electrode group support area arching away from the electrode group side relative to the reference plane gradually decreases, and the average height of the end plate located in the electrode group support area arching away from the electrode group side relative to the reference plane is H2, H2 = H + L / c; Wherein, the value range of c is 200 ≤ c ≤ 500.

3. The end plate according to claim 2, characterized in that, The end plate further includes two safety reserve areas, the two safety reserve areas are respectively arranged on both sides of the tab support area, and each safety reserve area is adjacent to one electrode group support area; The average height of the end plate located in the safety reserve area arching away from the electrode group side relative to the reference plane is H1; H1 = H + L / b; Wherein, the value range of b is 100 ≤ b ≤ 250.

4. The end plate according to claim 1, wherein The end plate includes an end plate body, a first support platform and a second support platform, the end plate body is located in the tab support area, the first support platform and the second support platform are respectively located in one electrode group support area, and the first support platform and the second support platform both include the support surface, and the support surface faces the electrode group.

5. The end plate according to claim 4, characterized in that The end plate body includes a base plate, a first side plate and a second side plate, both ends of the base plate, the first side plate and the second side plate along the first direction are connected to the first support platform and the second support platform, the first side plate and the second side plate are respectively located on both sides of the base plate along the third direction, and at least one of the first side plate and the second side plate forms a hollow part with the base plate, and the height of the midpoint of the lengths of the first side plate and the second side plate arching away from the electrode group side relative to the reference plane is H0.

6. The end plate according to claim 5, wherein The first support platform includes a first abutment plate, a third side plate, a fourth side plate and a fifth side plate, the end surface of the first abutment plate facing the pole group is the support surface, the third side plate is connected to the first side plate, the fourth side plate is connected to the second side plate, the fifth side plate is adjacent to and connected to the first abutment plate, the third side plate and the fourth side plate, and the average height of the ends of the third side plate and the fourth side plate facing away from the first abutment plate arched toward the side facing away from the pole group relative to the reference plane is H2.

7. The end plate according to claim 5, characterized in that, The second support platform includes a second abutment plate, a sixth side plate, a seventh side plate and an eighth side plate, the end surface of the second abutment plate facing the pole group is the support surface, the sixth side plate is connected to the first side plate, the seventh side plate is connected to the second side plate, the eighth side plate is adjacent to and connected to the second abutment plate, the sixth side plate and the seventh side plate, and the ends of the sixth side plate and the seventh side plate facing away from the second abutment plate are arched with an average height H2 relative to the reference plane toward the side facing away from the second abutment plate.

8. The end plate according to claim 4, wherein The length of the first support platform along the first direction is smaller than the length of the second support platform along the first direction.

9. The end plate according to claim 4, characterized in that, The first support platform is provided with weight-reducing holes, and the second support platform is provided with ventilation holes and weight-reducing grooves.

10. A power battery, characterized in that, The end plate comprises the end plate according to any one of claims 1 to 9.

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